Ok, thinking that I had arrows figured out based on knowing that the first two digits denoted diameter and then understanding the last two for wall thickness I was set. Also spent time testing how the 2018 that I was shooting acted, as well as reading all the info here for those of us that are slow learners LOL. When you look at the spine values that Easton puts out the confusion comes back! The 2018 that I shoot has a 0.464 spine factor, so I was going to go down, making the assumption of being somewhat over spined; but if I go down to a 2016 it has a 0.531 spine and a 2114 has a 0.510 spine. Is not the Higher the number the heavier spine?