Here's how I do it. First, use Hangar 9 titanium pro-links for your linkage. Next, check the center for each servo, be sure it's at 1500. Install & connect your servos to RX and link to elevators. Use the pro-links to equalize each elevator at dead neutral, and of course matching side to side. Next, with ATV or End Adjust set for maximum on your elevator channel(s), throw the sticks and see whether the two elevator halves are in sync at extreme up and extreme down. If they aren't equal, note which is more up, and which more down. Now use the programmer on the elevator with the more throw, and reduce it to where it's equal to the one with the lesser throw. Do this for both push and pull.

At this point, both halves should be in sync at neutral and at extreme throws. Now use ATV if to set your dual or triple rates, or whatever you're setting up. I try to connect my linkage so that maximum ATV will give me as much but no more than my high rate throws (taking the Goldsmith approach for maximum servo resolution).

BTW, I invested in a left-hand thread tap to re-thread the ball link on the wrong end of the pro-link. This makes it a lot easier than cross-threading the pro-link into the plastic--easier to install, easier to adjust. $13 from MSC Industrial Supply.