I always set the throttle from the idle postion on the TX. I want the carbarator to be open about 1/32 to 1/16th of an inch at medium trim, low throttle. Make sure the throttle idle set screw is backed out, so the barrel on the carb. can move to a completly closed position, but not so far out that the barrel can come out of the carb. Then I check the full throttle position. You do not want to have the servo travel exceed the throttle travel on the barrel of the carb and stall the servo. If you have to much travel, either adjust the end point adjustment; or, change to an inner hole on the servo arm. Making these adjustments, will likely mean starting from square one with the idle again.