I just got one of those mounts for my K31, but haven't done anything with it yet. A couple years ago I bought one from him for my M39.
I was well satisfied with it.
With my M39 I used a Burris Scout Scope. I believe it is 2x but am not real sure. The reason I bought the mount was that I wanted to see just how accurate the rifle was. I fired a few groups at 100 yards from the bench and then removed the scope and mount and returned the rifle to it's original condition. The scout scope was put back on my Marlin 444.
I own two K31s and am going to mount a scope on one and leave it. I happen to have two pistol scopes lying around the house here. I am going to use one that is 4x. I got the scope mounted on a used S&W 686. I didn't like the look of the black scope on the stainless gun plus 4x was very difficult for me to shoot on a handgun. So, I purchased a silver scope in 2x for the pistol. I sent the 4x black scope back to Leupold and had them rebuild it (just because) and it has been sitting ever since.
Now that you reminded me of this I might have to get working on that project today.