I printed the arm_v2 version last night, and tried it today. It works, and hopefully fits the Aerostruder, but I didn't like the wire trough. It was on the inside rail making the wire bend a bit over the outside rail. I've reworked the wire trough to now be on the outside rail, and that should work much better. I'll try to print it again when my current print jobs complete, but if you want to try it / look at it, it's called Arm-v3.stl.