Marc,
I have not owned one of those, but believe they have a "compartment" behind the butt plate for survival items. If that is true you might be able to fit a recoil reducing system in there. I'm sure that recoil is not an issue for you but is very real to your wife so that might help some. Also a bullet in the 180 to 230 range will help some as well.
One other thing as an idea would be to cast .45 bullets and paper-patch them. No leading and reduced recoil are some benefits. The only other idea for recoil reduction would be to use a "slower" burning powder, because you have more barrel to burn it in, and it will slow down the recoil impulse to more of a "push" than a "hit".
Hope she gets used to it, because they are a fine gun with lots of applications.
rich