You need 400s for sure and you really ain't far from needing 340s. I've had bows that I've set up with 28" arrows (I'm a 29 draw usually) and found that 400s with 100gr heads gave me a weak reaction... went up to 340s with 125s and had laser beams.

If you would like to shoot a lighter arrow, Eastons Flatlines are a pretty good bet.