[Otaku]

Have you considered a free-standing frame to support the FCG rig? I saw one at Wolfstone's site, along with a minimal how-to. You should be able to put this indoors without drilling any holes (I have the same restrictions LOL).

http://wolfstone.halloweenhost.com/HalloweenTech/fcgstd_FcgStand.html

 

[Otaku]

You could try some small weights, like split-shot fishing sinkers, at the bottom of the cheesecloth. If they're placed correctly, they shouldn't pull the ghost into odd positions and would help prevent the cloth from flipping up in a moderate breeze.