At what speed do most of you feel that fixed broadheads become troublesome? I've heard as low as 270 and as high as 300. I'm looking at getting a new (actually it'll probably end up being used) setup this summer and would like to graduate from my trusty muzzys and thunderheads to something like a snuffer/phathead/stinger/hellrazor/classic bears. I'll going to move up to 70# so reaching that 300 mark is a possibility. But I would like to settle on a target speed so I can build an arrow of appropriate weight and FOC Thanks.