Everybody has to start somewhere. The best way is to start with everything at maximum servo travel or, if there is binding at the maximum travel, as much as you can without binding. Use your linkages to get the throws set as close as you can. Chances are, unless you are looking for fairly hot control throws or are using extra long control horns at the surface, your throws will be too much at this point. Now turn down the end points to get the amount of control throw for high rates that you want. Then the last thing to do is set the dual rates up as a percentage of that high rate that you already set.

If you do it this way, you will be getting maximum torque from your servos, minimum stress on your hardware and servos, minimum current draw, and you'll be using the most teeth in your servo gears which minimizes gear wear. You'll also be giving your servo gears their best chance of avoiding damage in a crash. In the old days maximizing control resolution was also a benefit and still is, although with the fine control that any of the 2.4ghz radios have now that's really not a concern anymore.