Well Tim, I think this brace thing all depends on the bow and the arrow. The Howard Hill recomendation is 6.5" for the 70" model and 6.25" for the 66" model. Now with the Schulz reflex bows he says a half to a quarter inch less, but that is also understandable. The Schulz bows have thicker cores and lighter tips, could add to the stability and those end of the shot reactions as you mentioned. I have seen 5 lam Hills that shot just as good at lower brace settings and I have seen Hills that preferred what Hill company guide lines say. It all depends on the release and mostly the arrow. If one needs to really go with much higher brace, I would bet that a lower spined arrow would fly with a standard brace. I think Hill style bows like wood shafts that are not extra long. I helped a friend out with a new Hill. He showed up with a dozen 65# cedars that were ten pounds over the bow weight and a set of six graphites with a variety of inserts and points. The first thing I saw was that his graphite arrows were skidding hard on his arrow shelf. His cedars were way too stiff and flew loggy. We checked his nock and his brace. Lightend up the graphites, added weight, shortened one,(he hated doing that). Finally I got out some 50 pound arrows that were nearly net length for him. Close. Then I had him try a couple of my wifes 45 pound cedars, also nearly net for him, perfect. I had some of those that were uncut so I made a couple that would have some finger clearance with 125 heads, a bit of a kick. Brought his brace down to 6&1/8", perfect. He ended up getting 45-50 with 145 grain heads to match his Grizzly broadheads and they were perfect at a 6&1/8" brace. I suppose if he would have screwed the brace up to 6&3/8", he could have gone to 50-55 arrows and lined right up with the Hill suggestions for a 68" bow, 6&3/8" plus or minus an 1/8". In this case the shooter was a very good consistent shooter and it was possible to try to split hairs. I don't really think that it always needs to be all that complicated if the arrows are proper length cedars and not too stiff for the bow, a variety of brace settings would probably get the same results.