Trad Kid,
I've shot 6 so far with 5 making it less than 50 yards. All were shot with 2 blade broadheads from bows of 47-52 pounds. At 50 pounds, I would stick with a good sharp 2 blade broadhead. If you get good penetration with a double lung, they won't usually go over 40 yards. However, a one lunged bear can run forever. In shooting from a tree, full penetration will give you a very good blood trail and is more important than a big hole. The 6th bear I shot was not recovered. It was my first hunt and the outfitter had me 25ft up a tree. The bear was hit high in the near lung. However, the steep angle caused me to hit the brisket. With no bottom hole, I had no blood trail. The bear ran into a very thick beaver swamp and was not found until after I left. Stay around 12-14 ft up and take only side or quartering away shots. Good luck and hunt safe.