Earth to westerner !
I thought you had a CPA 44.5 Merwin. Me duh !
Ok, I want to change my opinion. I recommend you turn your Stevens into a full blown Shutzen rifle with three barrels. A .32, a .38 and a .25.
All Smith gain twist barrels. Get the triggers and wood from CPA.
A new set of Axtell sights to keep it traditional. As long as you're at it make the wood deluxe. It has to be checkered, maybe have Ken Hurst engrave a ferocious looking Russian Boar throwing some houndogs in the air. I'd do the action black to fit the mood of the engraving. Thats about it I guess. Oh, the barrels should be 30" long.
Most of the work on your part would be final assembly and money man.
A plain simple plug breechseater works great on the small .25 bullets.
If you need Ebony or Rose wood for the matching screwdrivers and loading tools to go along with this project , just let me know.
Man, this is really fun ! I'm sure glad were spending your money Merwin
Joe.