If you're using an ST7 that is extremely sensitive, why not simply lower your exposures so no rotation or drift is present. Simply stack many short exposures.
I have assumed you are doing this for research purposes as if you intended to take pretty pictures you'll want much longer exposures than 60 seconds (unless your talking about an NABG chip) to give a greater S/N ratio - especially for faint galaxies around the pole. Still think the wedge is a better option and reduce the size of your imaging train so it will fit between the fork arms.
http://www.allaboutastro.com/Article...vsrotator.html