After resolving my issues with limb alignment, I noticed that I'm now unable to tune my ACE 570's at 44#. My draw length is 28 1/2 and normally the Easton Chart has always been on the stiff side for me. Now I'm finding the opposite is true. The only differences is that I'm now shooting wood core F7's and a Fast Flight Plus string. I haven't really shot my HPX allot, but do many of you find that you need to go up a spine shooting a HPX? Right now it appears that I need to shoot ACE 520's to get a proper tune. Btw, I have always used a 120 grain point. Ant suggestions or comments?