This thread is nearly a month old, but I thought I'd throw in my $2 worth and expand on some of the points, the williams sight will work fine, they repeat without issue and fine adjustments aren't required in this game. You will usually be making corrections to the tune of a full revolution most of the time. The williams GR won't require a taller front sight, but the AG will, both clamp to the scope dovetail, but the AG clamps under the elevator, making it much taller. Everybody has to use a tube fed mag in lever, no box magazines are allowed, they give you 30 seconds to load, so no problem there.
Now to my real purpose of hijacking this thread to remind people that the piedmont gun club lever gun series will host their second of six matches, 4 best scores count for awards, this coming Saturday in Rutherford County NC. Practice starts at 10am and the first match is smallbore lever, target change and then pistol cartridge lever, then CLA on swingers will finish it out. Hope to see some of you there.