Here is what I see about heavy vs light poundage. If you shoot a lighter bow with a fairly heavy arrow for hunting, say 10-12gpp, it will work fine and kill many a critters. If you shoot a heavier bow with a fairly heavy arrow, the same 10-2gpp, you will probably get around the same speed, but because your arrow weight is much heavier, you will have much greater momentum such could help on marginal shots or on bigger, tougher critters.
I am an advocate of the idea that a guy should hunt with as much draw weight as he can shoot well under pressure situations! For me, that is 50# at my 29" DL. If you are just target shooting, go as light as you want, and have fun.
JMHO!
I am also pretty confident that if you have a well tuned 650 grain arrow, and you can shoot the bow well, you could kill just about anything you wanted to (at least in North America) with any of the bow weights you asked about in your original post.
Bisch