Before adjusting gear mesh, extend the counter weight shaft with gently holding the top of the shaft push / pull it back and forth so see how much play is in the worm and worm wheel mesh. A properly set mesh should show a small amount of smooth swing east and west where the gears are not engaged before coming to an abrupt stop on either side. If there is no backlash or wiggle there will likely be points that bind; it is too tight. If there is a large wiggle, backlash may be very large and you should tighten the mesh. If there is no wiggle, it is probably too tight and you should loosen the mesh.
RA gear adjustment starts by loosening the four 5mm hex bolts on the RA body of the mount to finger tight. (They should not be visibly loose.) They need to be tight enough to give us some feel for the gear mesh when we push on the RA but not so tight that it doesn’t allow the body to slide as we push the gears together.
Next step uses two 2mm hex head set screws to push gear mesh together or push it apart. They diametrically oppose each other; if one is tightened the other must be loosened. Always loosen first, tighten last.
Make a very small adjustment, perhaps 10 degrees. Grab the end of the counter weight shaft and check for wiggle in the RA axis; compare to the wiggle you felt before you started adjustment. NOTE: You may need to retighten the four 5mm bolts to get a true sense here if you loosened them a little too much. When you have achieved a small wiggle in the RA axis, gear mesh is probably as good as eccentricity in the machining of the gears of this budget mount will allow. Retighten the four 5mm bolts. Power up the mount and screw RA through 360 degrees listening for changes in motor sound pitch. If there is any stalling or significant lowering of motor sound pitch (indicative of stress on the motor) your mesh may be too tight and is causing binding: Loosen the gear mesh.