First off, what material and what thickness are you molding. The material used will dictate the vacuum hole size allowable. In most situations 1/16" is acceptable, but depends on the plastic, the contours and type of mold. If the mold is used for high volume it should be aluminum and it should be cooled with internal cooling or temperature control. If the mold is too cold then no matter the mold surface finish the part finish will have chill lines. Only testing will dictate mold temp. Part finish is only as good as the mold.