On the pushrod topic, I don't think it's enough to be able to move the servo when it's off by moving the control surface. My test is with the radio on I should be able to move the surface and move the servo off-center for just a second. That tells me the pushrod is stiffer than the servo is strong, which means it's strong enough to take any flight load it could possibly ever have. True enough, a trainer or even most sport planes will never put nearly that much strain on the servos, but there's no reason to fly with pushrods that can't transfer the torque that your servos are able to produce. My test also lets you check out the gear train if you're so inclined. I put some resistance on the surface, maybe 1/2-2/3 of the power the servo can produce, and I run it through its travel. If there's a bad tooth on the gear, I'll find it that way. I do that test for every servo on every new build and after every hard landing that I think might have done some damage.