Alot depends on your draw length, I draw about 29" and had a VERY hard time find ANY single shaft that would work. It also depends which bow you are shooting, some need more spine than others. About 10 years ago I was trying to work up heavy arrows for a 85# Black Widow, you can use the 2117 with the 1916 like Paul Schafer used for his cape buffalo and it works well, but has a very high spine. I saw a chart once that had the spine and weight with lots of aluminum duplex combinations. I NEVER found ANY wood shaft that had enough spine for me, except the Forgewood Battleshafts, which were compressed yellow hemlock, but even then I needed the 90-95 spine and they were impossible to get and are not being made currently. To get enough spine in other woods they will be large diameter, not what I wanted. I finally ended up using a 2219 aluminum with a 35-55 Goldtip carbon inside. Theses fly better than any other arrow I ever shot and end up at about 970 grains, but are fairly expensive and a pain to make. There are lots of other combinations of carbons and or aluminums available now.