I agree wholeheartedly on the "variance' in props, Steve. . my TOC100 would turn a certain Mejzlik 28-10 at 6800, another at 6600, a third at 6650, and a 27-10 at 6550. . .and the person who bought it from me says it does no better than a "standard" 3W100 for power. . . go figure. These 28" props are molded from CF/epoxy, that all came out of the same exact mold. Kind of gives a bit of weight to the "forget the tach. . just fly the plane" argument.