Well, I finally shot this Walker yesterday, and I'm happy to report that I won't need to make any alterations to the recoil shield. I do plan to get some Slix Shot nipples for it eventually, but I didn't have any trouble with the OEM nipples on this outing. I fired about 8 cylinders full, and the cap rake prevented any jams at all. With the exception of one cylinder, all were close to 58-60 grain charges under a .457 ball, as I wanted to test the "conventional wisdom" that heavy charges would batter the wedge. I don't know how many heavy loads it usually takes to batter a wedge, but mine came out of the ordeal looking pristine after 42 heavy loads.
I've a theory that, if the arbor isn't bottomed out, the barrel assembly can vibrate up and down during firing, which might contribute to those battered Walker wedges I always read about.
Coffinmaker has been teasing me about the heavy moving equipment I'll need to invest in just to hold and tote this thing around, but I was pleasantly surprised at the lack of recoil; 4 lbs soaks almost all of it up. I was also shooting a .36 cal. Colt Navy replica yesterday, and the scale difference between the two seemed to be almost directly proportional to the recoil generated by their loads. In other words, the feel of the Walker recoil wasn't all that different from the .36 Navy, and I was shooting both one-handed.
I need to shoot this more while I'm still relatively young, though; I can see where arthritic joints might have difficulty with the heft, as one's trigger finger is having to bear quite a bit of lateral weight just to hold the thing level.