This sounds like the same dilemma I'm in. I'm working on a Widebody and trying to figure out the split elevator linkage. I'm thinking of a pull-pull arrangement, but I need to figure out how to drive both halves from a single servo/tiller.

I've thought about the MK bellcrank myself, but I'm not sure about how to install it. Can it be installed in a fuselage without an access hatch?