You will need to move about 10cc of fluid to disengage the clutch. That means a 7/8" or 1" bore MC. I'm using a 7/8" bore Wilwood MC and the clutch is nice and light. The 7/8 has a slightly longer stroke than the 1" version and they both move about the same volume of fluid for the full stroke.
http://www.wilwood.com/Products/006-...CRMC/index.asp
Cheers