RE: They say 2 blade penetration is better....?
I'm not sure if this is in line w/ your question or not.....but......
2 blade heads have less drag than a 3 or 4 blade head, so technically they would penetrate better. But I am of the opinion that today's bows are SO efficient, and produce such excellent KE that unless you are shooting really light poundage you have no penetration advantage anymore with a 2 blade...