That's a good idea. And, as long as you hunt nothing larger, tougher or meaner than whitetails, I guess it's plenty valid.
Actually, what I said is "valid" regardless of the animal. No getting around the fact that energy expended in the ground after passing through ANY animal is energy wasted. It is of course obvious that some animals require more ke/momentum to achieve pass through than others but the principle still holds.
The lighter, faster arrow will be deflected further off course than the slow one.
Arrow weight alone is definately not the only consideration here. As you have pointed out many times, it is momentum which results from both mass and velocity that is the key to resisting deflection and increasing penetration. If the lighter faster arrow is carying more momentum as is the case with the 301 ft/sec 347 grain arrow vs the 221 ft/sec 600 grain arrow then the lighter faster example will actually penetrate more and deflect less. Only looking at arrow weight is very misleading. There's a little more to it than that! If you read Dr. Ashby's papers carefully you will see that it is momentum that is key.
Say the animal spooks and spins at the shot, and that perfect broadside shot turns into a rump shot. Where you needed only 18" of penetration into ribs and organ tissue to bury up in the mud on the other side turns into a situation where you might need 30" through heavy, dense muscle, guts, stomach and diaphragm just to get to the vitals. The light arrow might not retain the 'punch' to do the job.
I'm not sure where you are trying to go with this Arthur. Maybe I'm wrong but I thought you agreed that a 600 grain arrow at 221 ft/sec was adequate for "the job". I've seen you write many times that traditional archers have been taking every North american big game animal with this combo for years haven't they? In our comparison, the 347 grain 301 ft/sec combo is delivering both more KE and momentum and therefore more punch by any measure than the heavier arrow example.