I never knew about that sweet spot lol, but with the excals you dont need it..theyre already perfect.

I just went out n shot the 100gr 3blade Muzzys at 20 yards and after a little adjustment to my peep sight theyre shootin balls on lol..if i was shooting any tighter groups the blades would be hittin each other lol...

Took my old styrofoam target apart cuz the center was shot thru so much that i lost one of my old GT's after it blew threw the target..thats why i bought the new arrows ..they shoot great...built a new target and thought it would blow through for shure...all i did was stuff a box with cardboard and newspaper...works better than the old one lol stops the arrows after they penetrate about 9"...anyway thx for the help and good shootin