Keep in mind that the SRC+SSA is a schism of Griffin's G.D. and it operates, a bit or less, the same ritualistic way.
If I was to affiliate myself with the G.D., I would be extremely careful about which lineage I would choose. Definitely that wouldn’t be Griffin’s and also not Cicero’s. In Cicero’s, although I do respect him and his initiatory lineage, I know that if you are not a declared Christian, and especially if you are a Thelemite, you are never going to get past that portal grade. Pretty awkward, since Regardie was also a member of the AA and the OTO, and Chic was also in the OTO.
There is the Open Source of the G.D., which is Thelemic. Unfortunately, I don’t know much about these guys, but at a glance they seem decent.