I agree, it depends on the caller and the individual call. You can run through ten different calls with different cuts and perhaps find zero to ten that you can make a certain sound with to your satisfaction.
For me personally, I have found that a three-reed (.003 material), V-cut is the best reed/cut combination for the cluck/purr that gives me a realistic purr, along with that popping cluck you need to have for true realism. However, I sometimes find that in certain combo-cut calls, as well.
For kee-kees, I think most people need a call with no reed cuts for the easiest kees. For the kee-kee run, a combo cut or batwing with good second-reed exposure seems to work well for getting that clear kee-kee and good roll-down to the yelp.