The lighter you go in draw weight/kinetic energy, the more I think you must rely on momentum and arrow weight to get the job done. Don't even consider going less than 400 grains for hunting arrows. At 20 yards max, speed is a non-issue. It's far more important to have a QUIET, accurate arrow than a speedy one.

Those 280-360 gn toothpicks are good for target shooting and 3D but, IMO, using those ultra light arrows with a bow that's barely at the legal minimum for hunting is flirting with disaster. I'd suggest 400-460 grains - even 500 gns wouldn't be off my list for shooting broadheads at 20 yards and under - and a 100 gn cut on contact head like Magnus Stingers.