Keep in mind to shoot what you feel comfortable shooting, no matter the game or weapon, other than dangerous game. I've seen literally 1000's of customers over the years that struggled with too much weight and their shooting suffered a bit because of it. Someone who can shoot 42lbs well is far better in the field than a guy shaking and short drawing with 55lbs.
On a side note from my years in retail, I also think compound shooters are obsessed with speed numbers. So, many buy "speed bows" that are harder to shoot and then they match it with ultra light arrows, when what they really need in a moderate speed bow and heavier arrows, for the real world hunting they will actually be doing. In that same line of thought, I still had the sense that the traditional customers were interested shooting the very max weight they could draw, but they were missing the fact that shooting at the store range, while standing and in a tee shirt is far different than many hunting situations. I did my best to try and talk every customer down 5 pounds, when they bought a longbow or recurve.
What many forget or are unaware of is, under real world hunting, one often has to draw and hold, or they get hung up holding at half draw for a bit, even if they are normally a snap shooter. If the animal suddenly turns or steps behind a tree, one can hold lower weight, if need be.
My dad was a rifle instructor in the USMC. He was a big, big proponent of placement over power. Even though we had .338's, .340 Weatherby's, .375 H&H and even .458's, my dad's favorite round for Grizzly was the .300 Weatherby, which he used on 4 different Grizzly's. I had the luxury of hunting with famed Grizzly guide Clayton Mack. he liked the bigger guns like .338 and up when he didn't know the hunter beforehand, but he told me that he'd allow as low as a 7mm Mag, if he knew the hunter and had the sense of him. That's true for trad bows too. There's guys that can kill about anything with low weight bows.
To me, there is a connection between too much bow and too much rifle. Here's from Chuckhawks...
"Ideal elk cartridges. These are good cartridges to consider if you are buying a rifle specifically for elk hunting and don't mind substantial recoil and muzzle blast. Their principle drawback is that most shooters do mind the recoil and muzzle blast, particularly of the magnums, and simply cannot do their best shooting with these cartridges.
Bullet placement is the most important factor in killing power. (Memorize that sentence!)"
I'm not saying go out and specifically pick a 42lb bow for elk. Not at all. But if one has shoulder issue's, for which conditioning or working out has no impact, if all he/she can shoot accurately is 42lbs, then they can do so on CXP3 class game, as long as they are far more selective than the guy shooting 60lbs. The same is true with deer, where legal. You can kill any deer with a 35lbs recurve, but the shots need to be close and it helps if the animal is completely relaxed. As with choosing the perfectly matched bullet if using a lighter rifle, one must take more care on choosing the right arrow if shooting lower weights.
Anyhow, good luck on whatever you decide.