Wonderful rifle! I have a No. 1 Deluxe that I bought back in the early '80's. It's actually a New York rifle though I bought it just after they moved to Big Timber, MT. In those days you could order one up and have it in about three weeks. No more!
Mine is a 45/70 also. It has the old long throat for paper patched bullets so that's what I mostly shot in it, usually with a duplex load of 4 gr. of IMR4198 and the case full of FFG black. Put a card wad and a lubricating wad on top of the powder, then hand-seated the bullet with no crimp to keep from tearing the patch. Very labor intensive! Lately, I've gotten lazy so usually the old 500 gr. Lyman round nose bullet with a charge of 5744. That's a very accurate load too.
I don't shoot it as much as I used to, but I've used it on elk, mule deer, antelope, jack rabbits, coyotes, a couple of heifer cows that needed to be put down, cottontails, carp (it penetrates water well), and just about anything else you can shoot a rifle at. Penetration is unbelieveable - I've never had a bullet stop in any animal at any distance, including some good-sized elk taken at well over 200 yds.
The old timers gave up nothing when they used the Sharps. It'll kill critters today just about as well or better than any other rifle. Ya got yourself a good one there! Enjoy it!