Man, I have done some research in the "clipper area" and have some thought I think you might find interesting.
First off, It doesn't really matter where you stall the bag, what more important is how comfortable you fell setting it. Different players clipper different spots, but there's not much to choose from, rght? - either closed to the hell or toe area.
Lon Smith - right in the middle.
Ales Zelinka - right on the sole.
Mr. Vasek - very very often clost to the heel.
Chad D - close to toe.
EDIT: I have no pics of him, sorry.
I also belive that it depends on the lacing type you are using. If you compare Lon's and Ales's(?) shoes on the photos above you will see that Lon's lavers are much more loose and that IMO enlarges his inside surface whereas Ales has his shoes pretty tight which makes his insides a bit smaller but on the other hand makes him clipper more precise. I am not sure if that makes sense, but it does for me!
