Chris,
While going to slow will certainly cause a tip stall the Cap should have good slow speed charecteristics. Moving the CG aft will make the plane less stable not more and is good for snap rolls and flat spins but not landing or stall characteristics. The other major factor here is wieght and wing loading and depending on the plane itself I would recomend getting rid of anything possible to save wieght. A wing loading of more than 25 oz. will also give you problems where as under 20 and it would fly like a butterfly.