I use 242/243 blue Loctite, haven’t had anything come loose in quite some time. As was mentioned I tighten everything with both an Allen wrench and an open/box end wrench fully, with eccentrics away from the rails, then only turn the eccentrics in the (clockwise) tightening direction when adjusting. If I go too tight when adjusting I tighten from the Allen head side to loosen the v wheel on the rails. Make sure the fixed wheels (non-eccentric type) are loctited and fully secured before even messing with the eccentrics. If you decide to go with a heavier loctite such as 270 green, you can use the tip of a decent wattage soldering iron to get heat right where you need it to loosen(I don’t suggest anything more than the blue 242/243 though). Last tip, put the bolts fully through the bearings, then either apply loctite to the exposed threads only, or inside the eccentrics themselves (I put a drop of loctite on a paper plate, then dip a toothpick in to use as a brush). Most of the common loctite brand threadlocking liquids are anaerobic, they will only cure in the absence of air, so don’t apply to the bolts, wait to dry, then stuff them through the bearings, you’re just putting loctite in your bearings (not great).