O K, I know I am about to step into a BIG pile of "stuf" but, my feelings on this matter are that
"mechanical broadheads are for people who do not know how to tune a bow". Why would you want to put three opportunities for failure on the front of every arrow you shoot?
My practice arrows consist of nine arrows, three each of Rocky Mountain Premier, Thunderhead, and Steelforce all 100gr. I shoot them mixed together out to 70yds, if the group stars to open up I know I have to tweak the rest a little.
I use the stiffest arrow I can find, right now 3-71 ACC, with a 70lb Bowtech, paper tune to 1/4" knock high tear, then go to 40yds, shoot one broadhead, then one field point, shoot four of each. Usually there will be two groups with the broadheads about 2 to three inches below the field points. Now start raising the rest in very small increments, 1/32 to 1/16" until the groups come together.
Now all of this assumes you practice enough and your form is good enough to shoot that MEGA SPEED BOW you just bought.
Dave