RE: Servo Case Demensions ----Are They The Same??
My experience using Hitec, Futaba, JR, Tower, Cirrus, etc is that they are all pretty much the same size. They are not exactly the same dimensions, but very close and swapping one brand out for another is not usually a problem.
They do differ in output shaft diameter and spline count so the arms are not compatible. They also differ in rotation direction. Not all servos turn the same direction when the channel is in "normal" mode...