If your looking for gun stabilization have you thought about trying just a generic cheap rc flight 3 axis gyro or old heli tail gyro that no one uses anymore? I have a handful of unused gyros from planes and helis and I was thinking about incorporating one just for the turret traverse just to try it out. Not that that would be accurate for the two WW2 German tanks I have, but Im thinking about putting one in line with the turret channel and turn it on/ off with a 5th channel on the receiver. I dont know what tankers usually pay to incorporate a stabilization feature into their tank, but i wouldn't be surprised if it couldn't be done with a cheap gyro, or even gyro/receiver, This is of course providing that the elevation of the gun is operated by a servo and not that Heng Long elevation wheel thing they use.