Personally, I feel that the more vacuum, the better. You get a higher fiber to resin ratio and better strength. I go for max vacuum I can achieve without my pump running 100% of the time. When I need a good finish, I usually brush in a layer of epoxy (or polyester) on the mold first and let it gel in the open to "pretty stiff but still a little tacky". then I lay in the fiber and resin, then vacuum bag. I get a really nice finish that way. You might also try to use some carbon or glass "veil" fabric - it's an extremely fine random woven fabric to help relieve the fabric print-through you get with all these advanced processes and it keeps the pinholes from showing through so bad on the exterior (but you don't get a clean carbon weave pattern).

Even the resin infusion process, where the amount of resin is dictated by the amount of fibers, will leave voids between the fibers and the mold surface (or gelcoat). I infused a 1 meter R/C sailboat and it had pinholes in the glass from the voids (I had to paint it to make it water tight). My Nacra infusion has voids between the gelcoat and the woven glass fabric from that process...but it had an outer layer of gelcoat sprayed and gelled to the mold before the fibers were laid in and vacuum infused so the exterior looks fine (other than the crappy mold surface).

I don't know that the voids take away much strength from the lamination - so i don't worry about them unless I need a really nice exterior finish.