Not having any knowledge of the TX you have cannot give you a sensible answer on what it can do. I know that most TX. do have adjustment for servo throw. Yes if you locate the arm shorter on servo arm it will give you less throw.You could also locate it further out on flap horn reducing throw even more. However these adjustments will increase the required power from servo to move flaps. By the way if you don't have a fair amount of flying experience you are increasing the difficulty of flying successfully by using flaps.