mikebiz,
I just went with the recommended 6.5" from Craig's son Jon at Hill. I'd like to try a little lower as well. It really seems to like Heritage 250's, cut at 30" with a 200gr point, 3 rh mild helical fletchings. My nock height is at 3/8ths. Right now with that setup, My chronograph reads 165fps, I strung the widow and shot the exact same arrow, and wouldn't you know it I got 165fps as well as the average! I'm not very concerned with how high the speed is, but I do like to know what it is. I think these arrows are coming in at around 586 grains.
Cheers,
Barr