You failed to give us your arrow speed so we can't estimate you KE. This in turn makes it difficult to suggest a mech. But if your set-up generates at least 50 ft/lbs of KE then you could use a smaller cutting mech ( 1 1/8" Steelhead)). If that KE exceeds 60 ft/lbs then use a big cutting diameter mech like the GK Reaper or Rocket Hammerhead. You will find that a mech truly is field point accurate. But please understand that using a mech should be NO substitue for a perfectly tuned bow. You need that arrow flying as straight as possible to improve your penetration.