Stay with the heavier arrow. Shot placement is more
important than speed. If you plan to do any hunting
from outside a blind...turn your draw weight down
enough so that you can draw with no effort from a
sitting position and can hold it easily for 1-2 minutes.

Personally, I'm not a fan of leaving the arrow in the
bird. Over the years I've had a couple gobblers fly
off with my arrow on what appeared to be good hits.

Shot placement...Shot placement....Shot placement.