The spine charts aren't the law by any means. I'm usually in the 67-70 pound range. I have about the same draw length but prefer to cut my arrows to about 29 inches I think they are. Anyway, I first went with the 400s because that's what the chart said. They shot fine as long as I had field tips on them. When I put on the fixed blade, 125 grain heads the groups went to heck in a handbasket real quick. They grouped about like a nerf football 6 inches low left. Got a couple 340s and it all came back together. I've been shooting the 340s for about 4 years now with great results and no problems. You're right on the edge of should I or shouldn't I. I will tell you a stiff shaft shoots much better than an underspined one.[8D] See if you can borrow a couple or just get 3 and experiment before committing to a dozen or two.[&:] I personnally like heavier arrows so really didn't care if I lost a couple fps just as long as they shoot and penetrate. I shoot 125 Thunderheads. If you go with the 400s you could probably keep going to a lower weighted head to get the flight you want. In my case I already had at least 2 dozen of the 125 Thunderheads... mostly new.