Dang, Slufoot -- I have been thinking what caliber I might want if I can spring for another Handi this winter (depends if there is a bonus at the shop, and how big . . .) I always thought I'd go with an ought-six, but the more I hear about .45-70s, the more I lean in that direction.
You won't regret fitting a Williams aperture sight to your rifle. I have had a Monte Carlo stock and a scope on my .357 Max all summer for load development, but just now switched back to a straight comb and the little WGRS peep. Makes me realize why they're called "handy" rifles -- you can neatly carry the piece with one hand wrapped around the middle, where it balances. I fitted a Williams Shorty ramp and a brass bead front -- the Shorty mounting screw is placed to fit just right in the factory front sight hole, but I had to have the local 'smith open and thread it to 6-48 -- the factory screw is some near-microscopic little thing.
Will you be casting for the big .45? Now that my casting rig is back in business, the .45-70 looks even better. Yup, I think it's gonna be a .45 . . .