Well, that's two votes "for", and one "against".
I know with mine I always get the top-mount route and "float" them, and hitting the body or the cavity wall seems to happen at about the same point, which seems to be what Mr. Barbeau experienced with his VIP as well. I've been tempted a couple times to whip out the router and move that inner wall forward a bit, but then it gets dangerously close to the mounting bushing holes. That seems a bit scary - I gotta think you want some decent wood around those holes or they're liable to get sloppy over time. That would be NFG, as it would be difficult to repair.