Mary has an unbound and Lester has only 3 holes on front for control cavity. They had to play them per the contract but never played them stock in the beginning! These weren't just altered but Gibson delivered them to Les with cavity holes where ever he wanted and his has no jack plate on the lower bout side in the "there's no place like home" tube that the OP Oldskoolrob posted But Mary's does have 2 jacks and 1 unused side plate and jack?
But my point is that Lester's GT has no side lower boute jack and plugs on front whith his body only having 3 front holes drilled while Mary's "unbound" has an unused lower side boute jack and another on front where the tone knob is missing.
I might try this.
A master vol/tone setup would give you less loading when you have both pickups on. That position always sounds a little dull to me, and that would help.
maybe part of why ol les did it.