Interesting..... Ok...my Head, JJ's and Kastles,...skis I can remember most recently both needed to be moved forward....My Rossi S3's are right on from the factory.
Because I'm skiing much more upright than in the past, I find my current mounting point allows me to pilot my moved forward skis on groomed, crud and powder. Once there, I don't move them.
I should look at the ball of foot relative to center of running surface and see where I'm skiing. My binding mounting position has relied mostly on my "Spidy" sense, but worked out well over the years.
Jim I think it's important? to recognize that that one should be able to put equal amounts of pressure fore and aft to get the ski to do what you want. If it's taking more work to start the turn than to finish, I'd move the bindings up 1/2 inch. I can tell you from my most recent experience with my Kastles...I moved into an entirely new dimension of performance over that ski...it handles superbly forward for me, noticeably different and better.
Perry, rather than moving the binding back, maybe getting taller in your stance and trying to be more upright and working off the center of your skis when skiing powder....especiall y if they are right on the money on the groomed snow.
Best, G