Hmm. Well that clarifies things, but doesn't get me much closer to solving the problem.
Edit: Testing disc 2 (which is the one I was currently working with) and trimming the center channel to be largely dialog... I end up around -31db +/- 3db... which doesn't help if the loud passages are too loud even at -29db.
I think I'll stick with -28. It should get my normal listening to around -27/-28 and keep the loudest from exceeding -31... I think.