For some reason, fiberglass arrow shafts are as they say " as straight as an arrow". I taped one along the keel and had it overhang the stern. Heavy walled K&S aluminum tubes were clamped to the rudders. One of the rudderes was set parallel to the shaft at the Futaba neutral of 1.52 milliseconds. The other one was then set parallel to that. At least the are parallel at that point. Probably not at any other. Dan.