Bubbagates - Thanks for advice. The blue loc-tite was my next issue, you answered it. The servo arm screws are metric threaded, I am using the JR8411's all around on both planes, all ball links.
Horizons description below. I will source the allen head version screws.
Vince
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For giant scale and precision competition airplanes, JR’s DS8411 servos are the ultimate choice thanks to their high output torque and incredible accuracy and holding torque. To transfer all that available power to the servo arm, JR’s DS8411 features a composite metal gear train that includes a combination of hard anodized hardened steeland brass gears that are virtually unstrippable. This improving accuracy, combination of metals gives a long, backlash-free gear life. In addition, ball bearing spacing on the output gear has been significantly widened, offering greater radial output play and further improving accuracy. 155 oz./in. torque.