The best thing to do is test it for yourself.
What ever your maximum effective hunting range is,
test arrow weights at that distance and see how much
trajectory you can put up with, and still have decent predictable groups.
I’ve shot very heavy arrows and they simply die on the vine past 15 – 20 yards, the trajectory is worse than a bounding kangaroo with his pants full. You might be able to up it to 12 gpp, but still, it’s best to try it and see for yourself.
If your tune is spot-on, you can push the envelope by experimenting with number of fletches and their length/height. I try to squeak by with the least amount of square inches and still get good broadhead flight.