I doubt that the arrows are overspined @ #70. I have a bow that will crank down to #65, and my 3-60s are cut to 28.5" They fly and shoot very well, even with my bows that max at #61. According to the charts, I guess I should be shooting 3-49s. I can't believe there would be much of a positive difference. It seems that I end up right on the border of spine sizes with most arrows. I usually end up getting the stiffer spined arrows, and broadheads seem to fly well with my setups.