I have a Titan riser, Border medium limbs, 50# or so at 28", I draw about 30". Shooting 3 under, Axis 400s, 250 grain heads. I made an adjustable riser plate to adjust the center shot in and out. I have decent flight but not perfect flight. Should I try 500 spines or is there something else that is amuck?
400's with 250 grains up front sounds about right. Curious... do you have the tip of your arrow slightly past the string?
Don't know what you've done, but to start I would probably set the tiller from 0 to 1/16" positive, brace at about 8.25", and the nock set about 3/8" high and bare shaft to see where I am.
I have tried the arrow like you described but the best is way in, that is why I think the arrows are too stiff.
I will try the brace height like you said.