Can I ask something of SSPX groupers and others....
If you believe that the recent 'popes' are valid, then why are you disobeying them? Why are you teaching your children things that conflict with what the 'pope' has taught concerning heaven, hell, purgatory, limbo, sin.... ?
The reason why I'm a sedevacantist is because I feel I must until the church in Rome begins to teach truth again. If I recognize somebody as a pope, then that means I must obey him and the priests I receive the sacraments from must obey him formost, and particularly answer to the local bishops set in place by that pope.
Keep in mind that if I had no other choice, I would attend mass at SSPX chapels - as long as I feel they are offering valid sacraments and have not been compromised. But I would feel uncomfortable every single time I hear something coming out of Rome that I know is contradictory to what I learned in my catechism.