OP here, I'm still around!
You need a campy thread locking. Either the one with a C-diamond logo, or a Phil wood.
Cog-wise:
-you could probably get a non-campy 3/32 on there but you may need a thin cog shim behind the cog to get the lockring to properly engage, as campy cogs are thick
-AFAIK Campy only ever made 3/32 cogs in aluminium, all other campy cogs I've had were 1/8 and steel