3W ENGINES HELP!!!!!
The rear carb should not be a pain. Run in the engine on the bench and get everything adjusted and stabilized. Once it is installed in the aircraft, use another servo to actuate the choke lever, or run a rod out the side of the plane. Gas carbs rarely need to be messed with. One tip that will be of great help in getting reliability from the catb is a very good inline fuel filter on the carb inlet. Also install a filter on the pump you use to fuel the plane. The cleaner you maintain your fuel, the less carb problems you will have.
Vince