When I'm skiing well, I'm typically at @Horton 's level described above. About 90% of my passes are nothing but 32's trying to refine every aspect of the pass. I start and end there most of the time. When I feel I've fixed some things, I'll run nothing but 35's. Start and end there, for about 6 passes. For me, this exposes my flaws, then I can go back to 32 and work on those problem areas.
Off the water, closing your eyes and visualizing the pass is, potentially, more important.
You'd think you could run perfect passes in your mind, but that's not the case at all. I'm very visually oriented, so my flaws skiing are highlighted even more when visualizing.