It is a matter of prudence.

But a couple points:

1. You must support the Resistance as best you can, as they are the hope for the future. If you want your Latin Mass, you're going to have to compromise lower and lower to get it, as long as you depend on the SSPX. The sooner you start arranging for an alternative, the better. In other words, go ahead and yellow-light the SSPX, but don't green-light them!
Green light means "all is well". Even if you choose to attend the SSPX in 2018 for pragmatic reasons, don't forget about the deep problems that aren't going to go away.

2. You speak of this ideal, awesome SSPX priest and I don't doubt your sincerity, or even the fact that he's that awesome. But he's part of the SSPX, subject to the SSPX government, which is solidly going one direction (down, down, down). Your priest can only buck the trend for so long, and then he's going to have to either tow the party line and compromise, or leave. Countless priests from the Novus Ordo dealt with this. Talk to any of them. They wanted to be Traditional, faithful to God, but also stay on good terms with Rome for as long as they could. But eventually each one of them had to hop off the fence, and choose once-and-for-all: good or evil, truth or compromise, pleasing God or pleasing man.

3. The SSPX as an organization is sinking and failing, even if you choose to attend their Masses. Beware the new orientation and ideas about Vatican II, the conciliar church, and the Pope. Some priests won't even criticize the pope anymore, not even within charitable, Catholic bounds.

You must realize that the SSPX ship is sinking. They are moving closer to the Modernist, conciliar church, and closer to Vatican II, with every passing year. Is that what you signed up for from your local Trad lifeboat/chapel? I certainly did not. I want some resistance to Vatican II, and some fighting of Modernism the mother of all heresies.

Even if you choose to avail yourself of their sacraments, you need to have a game plan for what happens after your local chapel becomes another Indult parish (or literally merges with the local Indult -- hey, it could happen -- and in fact, it probably would happen.

When the neo-SSPX is finally regularized with Rome, how could Rome allow two of their own members to fight each other? That is to say, why would they have an Indult Mass in San Antonio (approved by Rome/ the local diocese) and an SSPX chapel down the road (approved by Rome/the local diocese)? It wouldn't happen. You can't have that kind of competition, that kind of redundancy, within the same organization. One of them would have to close, and all the parishioners would be directed to the surviving location.

The conciliar church does this all the time for practical reasons. There are only so many priests, the need is great everywhere, we all have to be reasonable, share resources, etc. Parishes close all the time once the population of the parish drops below a certain threshold. Parishes end up merging.

And then there's the brainwashing/frog-boiling aspect. It whitens my hair to talk to people at my old SSPX chapel, which I've only been absent from for 3 years. The people say things I never thought I'd hear them say. They say attending or starting an Independent chapel is somehow disobedient, bad, schismatic -- even though that's precisely what the SSPX has been doing since the 70's. Even today, the local SSPX chapel is no more "regularized" than the little Resistance chapel close to me. The SSPX might be bigger and have more money and people, but that doesn't give them any free jurisdiction or Roman approval. They are still just a lifeboat. Hopping in a lifeboat to save your faith is NOT disobedient -- in fact it's the very essence of obedience. We must obey God rather than men.

Even the terms here a vague.  What does Red Light actually mean?  If you treat them practically like, say, Orthodox schismatics, then that would practically be schismatic.  And then why would you red-light the entire SSPX?  If you happen to have a priest that talks mostly about spiritual matters and barely speaks of the Church crisis (I've known many like that) or else is less liberal vis-a-vis his position on the crisis, then there's little to no harm to assisting at Mass there.  Also, is the alternative to become a Home Aloner?  What's worse, running into some liberalism at an SSPX center or being deprived of the Mass and Sacraments?  Most of us needs these to keep alive spiritually.  Until there' s a problem with validity or they embrace actual heresy (a high bar), I don't think anything more than a Yellow would ever be warranted.  There were lots of liberals and modernists floating around even before Vatican II, but people still went to Mass and received the Sacraments from them.

It's complicated too. Does once-a-month Mass at a Resistance-affiliated location count as being a home aloner?

Yes, it is ... with a lot of prudential judgments required.  In not too long, one would have to treat them the same way that one would treat a Motu group.  Is the priest valid?  I'm not sure if they still have the Cor Unum out there where you can look up who ordained them?  Even if he's valid, were there other dubious priests floating around who may have consecrated some of the Hosts in the tabernacle?  Is the priest liberal?  Does he say scandalous things that could harm the faith of your children?  Sometimes it's worse to hear these things from someone saying he's Traditional than for some guy officiating at a clown mass.  Could you do a quick hit-and-run just to receive the Sacraments?  Is that the only place you can receive Sacraments within a 300-mile radius?

Yes, it is ... with a lot of prudential judgments required.  In not too long, one would have to treat them the same way that one would treat a Motu group.  Is the priest valid?  I'm not sure if they still have the Cor Unum out there where you can look up who ordained them?  Even if he's valid, were there other dubious priests floating around who may have consecrated some of the Hosts in the tabernacle?  Is the priest liberal?  Does he say scandalous things that could harm the faith of your children?  Sometimes it's worse to hear these things from someone saying he's Traditional than for some guy officiating at a clown mass.  Could you do a quick hit-and-run just to receive the Sacraments?  Is that the only place you can receive Sacraments within a 300-mile radius?

Interesting point: I am not a red lighter, but I would leave my chapel tomorrow if they assigned a doubtfully ordained priest to it.  But even that, I guess, would still be a yellow light, because the condition at my chapel would not necessarily apply to other chapels.  Not sure how prevalent this problem is in the SSPX throughout the world, but I know several doubtfully ordained priests (both SSPX members and associates of the SSPX) are or have been floating around the USA (e.g., Monsignor Byrne, Fr. McManus, etc.).  If one of those showed up at my chapel, I might just as well seek out a priest ordained by a Thuc bishop (i.e., questionable).

And what about those of us with children?  The priest may be great...but what if he's replaced by a liberal one?  Wait until he's gone and then return?  What sort of message does that send?  Small children don't understand that; they'd see it as "Daddy and Mom don't like so and so...but they liked this one"  Ok; so to them it appears alright that if you don't like a particular priest, you don't have to go to Mass. 

Or Confession.  There's no way to control the spiritual advice given in Confession.  What if it's liberal in some way?  Your child wouldn't know!  My mother went to Confession to a visiting priest recently, and he started rationalizing FOR HER that this wasn't a sin...this wasn't mortal...this was ok...etc.  A child wouldn't know what to do with that.

And then there's the peer influence.  A lot of SSPXer's I know that are raising children the same ages my children are...just don't care as much as we do about TV, music, dress, etc. 

Maybe we're taking the easy road out by Red-lighting, but I don't think so. 

And what about those of us with children?  The priest may be great...but what if he's replaced by a liberal one?  Wait until he's gone and then return?  What sort of message does that send?  Small children don't understand that; they'd see it as "Daddy and Mom don't like so and so...but they liked this one"  Ok; so to them it appears alright that if you don't like a particular priest, you don't have to go to Mass.

What if he isn't replaced? or if the next priest is even more conservative than the one replaced? Then what? Would that mean you've been going to a liberal priest the whole time? Honestly, this is a bit schizo.

Parents are the first source of their children's education - the parents need to teach their children to understand so that they see it as it is and don't see it as  "Daddy and Mom don't like so and so...but they liked this one" etc,.

Or Confession.  There's no way to control the spiritual advice given in Confession.  What if it's liberal in some way?  Your child wouldn't know!  My mother went to Confession to a visiting priest recently, and he started rationalizing FOR HER that this wasn't a sin...this wasn't mortal...this was ok...etc.  A child wouldn't know what to do with that.

Again, it is the parents' job to teach and council their children, the parents must tell their children "what to do with that" so they will know what liberal advice is and what isn't, also what they should do in the confessional if/when they get liberal advice. Don't forget, if the child is going to confession at all, then the child has reached the "age of reason". It is the parents who do their children a terrible disservice by not giving basic instructions on liberalism, etc. because they assume children could not understand basic instructions regarding this situation. 

And then there's the peer influence.  A lot of SSPXer's I know that are raising children the same ages my children are...just don't care as much as we do about TV, music, dress, etc.

Unless you're living off grid, this goes for +99% of the population, it is not unique to SSPXers.