My fiancee shoots a Hoyt MT Sport at 48 lbs., and this summer when I asked my pro shop guy about a different broadhead for her, he handed me a pack of Sonic 85 grain 1" cut. She had been shooting Rocky Mtn. Premier 75's but we always had to resight her bow for use with them. The 10 grains of more weight we had to resight with heavier field tips,but when we put the new Sonics on, she was still dead on.
I shoot the Rocky Mtn. Advantage 100's, and have ever since they came out. They fly like darts for me and have never had to move my sights with them, but it seems everybody and every bow is different.
Click the link to see the Sonic heads.
http://www.americanbroadhead.com/sonic_heads.shtml