TubbsTru,
My thoughts on this are just speculation based on what I've actually tested regarding draw length and extending that observation to how moving the handle forward changes the effective power stroke of the bow, assuming that the same strung profile is retained. I've owned many bows, but none with a forward set handle, and I'm sure that many bowyers, like Sixby, work hard to optimize limb design for their chosen bow geometry.
Speed/# is really important to me as I've had multiple shoulder surgeries (and am trying to delay the next one!) so I look for bows that offer great speed/# and use that performance to reduce draw weight and still throw a heavy arrow. I happen to have a long draw, thus the tests that I referred to originally. BUT, shot placement trumps all else, so I'm unwilling to shoot a bow that's overly sensitive to release. The grand compromise;-), and the answer is different for just about everyone.