I know I wouldn't shoot less than a 400grain arrow at game. In fact, I like 450-500gr. Penetrates much better than a light setup, quieter, and seems more accurate for me.

But in your case, how heavy they should be, is up to your manfacturer and you. I know PSE, bowtech and most companies tell you thats way too light. And might warp the cams, or crack the limbs. I know if I was you, I would shoot at least a 400gr arrow. But with your very short draw, you might be fine at 4gr/lb draw.