I love to tinker. But Extreme forwar of center is not something I have figured out. I've tried it a number of times. Maybe it is my shooting style, but normally, My arrows do weird things. I mess around with various sizes of cabon arrows. It seems that no matter what I do, my arrows show stiff. Even when I shoot a setup that I KNOW is too weak, my arrows will bareshaft left. (I'm a right handed shooter). I then procede to go up in spine, and still I get the same results. Maybe I just don't get it, but I have had pretty good luck with arrows set up the normal way. I do appreciate the fact that extreme forward of center penetrate better, but until I get it right...I'll just stick with my regular arrow recipies.