OK, I'm editing this and here's why...

I didn't like the layout of the rear servo bays. I couldn't see how they would make the geometry work with the long arms I wanted to use. So I spent some time try out a bunch of different arms and linkages and have found that the layout will work as long as you use 1" or so arms and not much longer than that. The geometry is still a bit funky for my taste but it will work. I just like my elevator halves to have the same geometry, I guess. I think the layout used for the dual elevator servos in the 67" Fusion would have been better but I don't design planes, I just buy 'em and fly 'em.

My 79" Yak has the same differing geometry on each half and I was able to get it nearly perfect with some end point adjusting and tweaking of the linkage.

The easiest fix if you want to get the elevator servos to be in mechanical unison is so put in an elevator servo bay just forward of the upper bay. Then you'll have both elevator servos following the same geometry in relation to the stab (one will just be a little farther away but that's not a problem).