How heavy can you shoot EASILY? I have over-bowed myself time and again when I was first shooting a bow. I really was caught up in Magnum Thinking. Bigger guns/bows kill better, right? I don't know why I bought in to this concept, when I had bagged two deer and a mess of antelope with a .223 already.
45-50# draw weight will easily break the heaviest rib in the biggest bull elk in the Rockie Mountains, so long as the arrow is well matched to the bow and is tipped with a properly sharpened broadhead.
However, if you are struggling to get a good release causing arrows to wag like a happy dog's tail at dinner time, you are risking hitting the animal at one extreme or the other of the wag. That can cause the arrow to turn on impact and go all catty-whompus into the animal. I saw that happen with my first deer. What should have been thru the bottom ends of both lungs caught just a little of one lung, some liver, and a lot of gut. What should have put a deer down in minutes left a deer struggling most of the night until she finally expired.
And it wouldn't hurt to study up on the internal structures of the elk and the bear as well. Their lungs/heart/liver are placed somewhat differently than those of deer. That means you need to adjust point of aim for each animal slightly in order to get the best results from the broadhead.