One only needs to test his own bow with various weights of arrows through a chronograph and you'll see that you will gain about 3 to 4 ft. lbs. K.E. with the heaviest arrows. How much of this will make a difference on our deer?? not much.
I agree completely. A good sharp broadhead riding on even a 5 grain/pound bow arrow combo and shot by an archer of average strength is a deadly prospect.
BTW, thanks for the encouragement. And congratulations to your wife!