Set your radio to 100% travel using the ATV or end point adjustment and leave the D/R alone for now. First, set your control linkage mechanically to give you close to the throw you want and still have mechanical advantage. The servo arm should preferably be shorter than the control horn. You have several holes in the arm and horn to achieve this. Mechanical advantage means the servo doesn't have to work as hard to move the control surface. Now that you have that, adjust the end points of travel for the desired control surface travel.

When that's done, IF you need dual rates, set them now. A typical setting is 60% of full throw.

Dr.1