Try as hard as I can...
well, you can only try. It really depends on the sculpt and how particular you are and what is that mini used for.
Good sculpted mini have very good defined eyes (sad to say, GW mini eyes is terrible) with proper iris defined and the pupil protruding slightly above the iris. When conditions are right (sometimes I use the knife to cut it myself), I will paint the works. Otherwise, what the heck, the pupil is all it needs (dwarf have very small eyes. Nearly impossible to fit everything in)
Moreover, if that mini is meant for tabletop gaming, imo, don\'t bother (can\'t imagine doing that for 20 minis in a regiment). Otherwise, go for it.