I haven't been here or caught up on any new methods but sounds to me like you need to use a thinner mixture and lay it on real light. I dont remember seeing any roller marks when painting, or if I did, they went away on their own when rolling over the area after applying the coat (to even things out). Thicker paint will just stay there and not self level, and too much thin paint would probably run.

By the way here's a pic of my Dart on the road..there are a couple scratches on it from working on it, so im thinking of going with another couple light coats of the old Hatteras white.