A tithe is given to God, like Abel was taught to do, handed down from Adam.
If this helps,
In giving “Sunday collections”, it is a tithe of the first fruits of yourself to God: an oblation of a spiritual offering to Him, and or, an oblation of a material offering to Him. The oblation of a Spiritual offering is easily understood. The oblation of a Material offering is given to God, to His ministers in His Catholic Church for the sustenance of their needs, as with, God will inspire them in the rest of His will, what to do with the “abundance”…
When we “tithe” we cannot do so to an entity that does not have the Faith –it is not to God; it is to man.
Therefore, when we “tithe” it can only be to those who have the Faith. As far as the present SSPX crisis, it would be in your conscience for now in what God had provided for you to know where the True upholding of the Faith is, and from there, where to “tithe”.
As I remember Fr. Peter Scott writing on this topic, he said that we must primarily “tithe” and give support to the place that we go to Mass; not to another place that has the same Mass. I can understand this, but if that primary “place” is now compromising subtly, or wholesale in the Faith, it is then an entity that is willfully choosing to lose the Faith. Therefore, it is not to God; it is to man.
Objectively, Fr. Pfeiffer, Bishop Williamson, and the others are clearly upholding what the Faith is, and where it is in the Catholic Church. Therefore, in this present crisis, it clearly shows that the primary “tithe” would go to the support of those priests, and Bishop, who are not compromising, and still doing the will of the Catholic Church that they were ordained in -doing God’s will- regardless if liberal leaders want to throw them out (like the other liberals leaders had done to Archbishop Lefebvre); and secondarily, a “tithe” to another place until such circuмstances reveal to yourself that you cannot support the (vain) efforts of those others endangering the Faith, and the Faith of your children.