Answer

The tithe of money has no clear source, and its parameters depend merely on the reasoning of halakhic decisors. In principle, it is apparently only a custom and not an actual law, so there are really no strict limitations. But the view of most halakhic decisors, and that also seems to be the straightforward reading, is that the tithe is intended only for the poor. Someone who has the practice of giving it for other purposes, such as Torah study, has no reason not to give it to the Third Path as well, if you believe in its goals and understand that it works for the sake of Torah and to prevent desecration of God’s name.