I've always hunted elk with bows in the 65 to 70 pound range, but this year I got a new longbow from Dick Robertson that has 52# at 28 on the handle. My draw length is 30 inches, so not sure what it pulls there, but the arrows weigh 625. I've used the WW's the last five years and have killed five elk with them, so don't feel I need to change broadheads. I might shoot wood this year, but the carbons I've used had all the weight on the front.
This year will be my 38th consecutive year hunting elk, 31 with a bow. The one thing I learned is NEVER shoot an elk in the shoulder blade with an arrow. It may very well kill the elk, but it won't be close to home when it dies.
Now, as far as empirical data. I hunt with a group of six to nine stickbow shooters in camp every year. My bow was always the heaviest one in camp, for pull. The rest of the guys favored the 55# range, and they shot (shoot) them well. I think last fall we tallied up some numbers and for the last ten years the elk tally was well over 70 animals. The arrows were wood, carbon and aluminum (the correct pronunciation is AL-U-Minium, according to the OZ guys)but the majority were with wood. Back in the early 90's I shot a bull in the neck with a Doug Fir arrow and he dropped in his tracks. The arrow probably weighed over 700 grains, but I don't know for sure.
Anyway, shoot heavy arrows out of whatever bow you want to use and it should work.