The Byron aeroplanes, being scale, traditionally build(t) into very, very heavy craft.
This is not really what you want in an IMAC plane... or any plane for that matter.
They where designed and produced back in the times where people didn't really grasp this concept.
It sure does (did) look nice though.

CG will be on the spar for starters, throws? Dial in some normal ammounts and use the dual rates to cut 'em down in steps on the elevator/ailerons.
Choose what your happy with.