I have to fight over-the-top swings quite often. I find myself wanting to use my dominant right side (right hand swing) from the top. The only cure for me is to think left side swing thoughts and just let my right arm come along for the ride....actually feel that my left hip pulls my left Lat (and shoulder blade through the ball).
My wife plays also and it helps her to have a slight open stance but shoulders square to target. Encourages an inside to out swing path if you have a decent shoulder turn in backswing.
As far as keeping your right shoulder behind you.......I recently watched a video from a female instructor that said to keep your back to the target as long as you can in the down swing. Of course, you still have to initiate the swing with your legs/hips. Good luck, it is tough to get rid of old habits.