RE: Penetration differences
The whole point of my post was to say that if you are shooting anything about 50# and hunting deer, then it doesn't matter. If guys would spend as much time perfecting their shooting form and super-tuning their bows, and learning something along the way they wouldn't have time to worry about crunching numbers that don't really mean anything anyway.
And it's stupid to compare penetration differences in foam targets. Foam is not flesh.