I have found with my bows that if I take a 175 grain tip or broadhead on a shaft cut at 29 inches for both 250 and 350's, I use the stock aluminum insert for the 250's and a 100gr. brass insert for the 350's they fly just about right for both. 250's about 570 gr and 350's about 670gr. With my 61#@28" bows I'm pretty happy. I probably draw slightly less than 28", I havn't rechecked my draw length lately or since I changed my anchor awhile ago. I also use the 150's with a 100 gr tip when I want bullet like speed! This is why I like the Heritage shafts, so much versatility, same components. When I go down to 55-56# bows I add 225-250gr tips and my arrow weight increases to about 740gr with the 350's and a 100gr. less with the 250's.