Howdy
One solution to not getting your knuckle battered by the trigger guard is to not place your knuckle right behind the trigger guard.
Take a look at the shape of just about any modern semi-automatic pistol. You will never get your knuckle whacked because it is physically impossible to get a finger behind the trigger guard.
Unfortunately, revolvers are different, they are designed to have a finger on the grip behind the trigger guard. The standard Ruger grip pretty much duplicates the Colt Single Action Army grip, which in turn is the same as the Colt 1851 Navy grip.
I discovered a long time ago that if I leave about 1/4" of space between my knuckle and the rear of the trigger guard, it leaves enough space that the trigger guard does not strike my knuckle. The secret is to not try to cram the entire hand onto the grip. Instead, try holding the gun with the pinky curled under the grip frame. This frees up enough space so that the shooter can slide his hand down just a little bit on the grip, leaving that magic 1/4" of space between knuckle and trigger guard. Yes, this is just the opposite of what we have always been told about grasping a pistol. We have always been told to hold as high as possible, to help prevent muzzle lift from recoil. But it really is a moot argument if the trigger guard is whacking us with every shot and calling us to flinch.
The SAA grip, and the standard Ruger grip, was designed to roll in the hand with recoil. Once one understands this, it becomes pretty easy to grab the revolver low enough on the grip every time so the the gun rolls in recoil, and the knuckle does not get battered. At that point, it really does not matter how much the gun recoils, the amount of bullet rise will be consistent from shot to shot. It can be allowed for with fixed sights, and it can be adjusted for with adjustable sights.
I shoot Colt, clones, and Rugers with full power 45 Colt Black Powder loads. They may not have the same recoil as a 44 Mag, but it is still a pretty respectable recoil. When I first started shooting Black Powder in CAS I was convinced I would need the Bisley grip to help me combat the increased recoil. So I bought a Bisley Vaquero. I only shot it at one match, I discovered I preferred the standard grip and I held it as described. I do not hold a death grip on the pistol. That is a great prescription for flinching. Instead I grasp the pistol rather lightly, with my pinky curled under the grip, and that magic 1/4" of space between my and the trigger guard. I can shoot full powered Black Powder 45 Colt loads this way all day long, I never get my knuckle whacked, and because I keep flinching to a minimum I usually hit what I am aiming at.
Try it, you might like it.