So, a little technical data. Arrow I ended up with weighs 588gr. Bow is 40#@28", I draw 31" so I estimate that to be around 49# at my draw length. The math there works out to 12gpp for the arrow and I was getting a consistent 160-161fps through the chronograph. I tried .500 spine and couldn't get anything to work in a safe weight, moved to .400 spine and eventually got really good flight, but damn heavy. Ordered some .450 spine in the same shaft and will play around with them later. Hoping to end up with an arrow that shoots same speed as my heavier draw Toelke Lynx that I will use to hunt elk with in a couple months.