RE: Broadhead weight
You might have to cut down your shafts to get a bit stiffer spin. I say that because you mention the arrows are tuned to 125, there for a heavier head would make the shaft under spined. You might just have to cut a tad off to make it work. Since you are shooting carbons, you can strip off the fletching and cut from the back then refletch. Just retune the arrow with the weight you choose. I have never shot anything with a 50lb bow so I might be wrong here, but I think you will be ok with 125grains. Some others here might know better. Ive never had a penetration problem shooting 125 grain heads from my bows. But the lightest I hunt with is 58lbs at my draw. I will be using 125 grain magnus this season with a 65lb long bow.