A nice little article that supports the necessity to slow down drills (very slow) if you want to make positive stroke pattern changes.
www.usaswimming.org/.../ViewMiscArticle.aspx
Isometrics can prove to be priceless when trying to make positive stroke pattern changes. I suggest using three isometric exercises that mimic three different positions at three different phases of the stroke you want to change. For instance, a backstroke recovery isometric, an EVF backstroke Isometric, and a backstroke finish isometric. You can incorporate these before practice, after a set, or after a practice. You can also increase stress by using a stretch cord or weights. It'll take three to eight weeks to produce a better habit so be patient. Good luck! Coach T.
And don't forget, it's better to love a short girl than not a tall.