Draw weight and arrow length?? If your shooting this bow at 65 pounds or more and you dealer set you up with a 350 spined arrow... he's an idiot. I suggest that he set you up with properly spined arrows from the get go.

You are also going to have to be meticulous with broadhead alignment because of the long insert/outsert that those armor piercing arrows use. Any minor misalignment with the insert to the shaft will be huge at the broadhead. You must ensure that the broadhead is spinning perfectly with the axis of the shaft. If it isn't you will never get good arrow flight.

The dealer is right in that as speed increases broadhead flight gets more and more finicky. That's why I set up my arrows to shoot 270 - 280 fps. For instance I am shooting the destroyer 340. I built my arrows to weigh in the neighborhood of 525 grains and they are shooting 277 fps. Arrow flight is perfect with field tips and broadheads. I have done the speed thing and the little gain in trajectory isn't worth all the extra aggrivation.