I did a quick search, but I didn't find the answers I was looking for. So wondering if everyone might be able to help. I am working on an arrow for my new bow and I was thinking I would be around 650 grains, but now it looks like I may be around 720.
I draw about 56 pounds and wondering how much difference there might be between the 2 arrow weights. I have not gone out and shot the heavier arrows, but I also do not have a 650 to be able to compare it to. Would there be that much difference in arrow drop out to 30 or 40 yards, and if so is it a lot more challenging as a shooter to shoot it proficient? I am not looking at harvesting an animal out that far, but I do want to use one arrow and stick with it.
Any input or advise would be appreciated!

I shoot about the same weight as you at 29", and shoot 650 grain woodies. About 25 yards is where I can start to tell a trajectory differance. Up close(inside 20) I can't tell much differance between light and heavy arrows. But practicing at 35-40 I can tell a big difference between my woodies and lighter carbons that are about 525. So yes, at the long distances it's definately( to me at least)more difficult with heavier arrows.

I've experimented a lot with that. For me, the point of diminishing returns with the bows I shoot is around 750 grains. I prefer to be in the 600s, but that hot 62# recurve I have casts arrows over 700 grains with no problem. With the 40# limbs I stay around 600, and it handles them with no problem. Being perfectly tuned with the arrows is a more important factor, I think.

The math is pretty simple. If we assume an average performing bow, say 185 fps at 9 gpp, then you're going to lose about 9 fps of initial velocity between 650 and 720 grains. At 40 yds, you will hit 2.2 inches lower. If you misestimate range at 40 yards by 10% (if you hold for 36 or 44 yards when its really 40), you'll miss by 10 inches with a 650 grain arrow and by 11 inches with the 720 grain arrow.