RE: Sight Pin Spacing..
^stated well. It cant work physically at all yardages because of wind drag which slows the arrow speed down. If the coeficiant of drag was gone and the arrow was a constant then your sight pins would be the same distance apart every 10 yards out to infinite. But, wind drag slows your arrow down the further it goes thus, making the pin gaps further at further distancces. if you had a 60 and 70 yard pin, the gap between those two would definately not be the same as the 20-30 pin gap. understand?
as far as the idea for that working on all bows, im not really sure b/c each bow is subjective to arrows and tunings that could cause odd results.
Derek