I would work on more accuracy and maybe bump the weight a little, but not out of your "totally in control" zone.
What has been said about shot placement and the hunters ability to hold off on shots that do not assure penetration, is at least as important as anything else.
A lot of elk are taken by accurate, careful archers using bows that are pretty light.
In the end, it comes down to the archer, not the tackle. I read about guys losing animals using the bigger weights, so the argument of how many are lost to light bows is not without its flaws. I think most animals are lost by shots that were in poor judgment- pushing the limits of the archers ability, not because of bow weight etc.
Sure fine tune your tackle and go as heavy as you can shoot well, but don't think its the tackle that is going to kill that animal.
You are, with a shot you can make.
Joshua