What kind of surface finish is required for easy lease to work effectivly?
Does the surface have to be finished to a high gloss, or would a 400 grit finish for example still work OK?

I think that 800 would be ok but just to be sure apply couple more layers of agent, or put some more effort and sand it to 2000, or use PVA because then there isn't really matter what the finish is.

~~~Everytime I hear sound of demoulding part I have eargasm~~~