The only number that really matters for penetration is the momentum figure. With your numbers you are looking at only a 3% gain by going to 70 pounds. The 70 pound draw is only .03 higher than the 60 pound setting. 70 has some advantages when talking about arrow trajectory and yardage estimation etc. but it would appear that your arrows are already absorbing all the energy that can from the 60 pound setting. If you choose to go to 70, I would also suggest getting heavier arrows to more efficiently use the added power.
