When you say hesitation do you mean it's bogging? RPM's drop and kind of limps along but runs great when you start to accelerate?

Trouble uphills especialy off start?

Does the car want to stall when you cover either carb with a shop rag?

12 BTDC is that with the advance on? what RPM? that sounds a little on the high side.

Also, if you have a caliper and can measure that distance I would appriciate it.

Where did you get 56 mm for the idle adjuster nut?