RE: If you could choose...
 

Again, I bring up my elk hunt, pass through and returned home to not pass through on a doe.....same shot area, the doe being closer than the elk...penetration is influenced on so much more than arrow thickness but I understand what your asking. I don't think you can get thinner than those formerly pultruded carbons, Beman 70/90's....

The difference in the arrows you question, theoretically might have less with the ACC's but it's irrelevant with all the other outside factors that influence penetration. You can take the same shot with both arrows and either one would out penetrate the other on any given day in the real world but again, theoretically, the smaller will penetrate more with equal weight being the same. In the ground is in the ground tho..;)

RE: If you could choose...
 

bemen..just cuz