Is there a servo that could be used in the small cutouts provided? The Integral directions lists a cutout that would fit the 3421 without modification. 15 x 32. If this is the smallest size servo that someone might choose then I think it would be no different for the manufacturer to make the opening that size. (Monor point on a nicely produced airplane)

On another note I was waiting for some 3mm threaded rod. I ordered a couple of pieces from McMaster Carr yesterday at about 4PM. They arrived UPS ground this morning. Pretty cool.