Hi Chris,
I can't help you with the 64bit question, only to say that Mesu users on SGL have never complained about 32bit SiTech on 64bit PC's.
You may have to describe your problem on SGL in the mounts section. Lot of Mesu gurus over there.
Or you could join the Yahoo group for SiTech.
https://groups.yahoo.com/neo/groups/SiTechservo/info
Cheers
Bill