Dave, Its up to you which broadhead you use, I carry both Mechs and Fixed in my quiver. Muzzy is a fine head and will shoot accurately w/ a well tuned bow, Ive killed many deer w/ the 3-blades. I make sure my fixed heads, mech heads, and field tips all group together.

One thing to check when you tune is arrow spine. I didnt run the numbers from the arrows in your sig, but it helped me a lot to bareshaft tune. I could only do so much w/ my rest and nock point to get a good tune, after a bareshaft tune i discovered my arrows were underspined and i had to make some corrections to achieve good broadhead flight.