I have used 4759 with very good results in several trapdoors and Sharps rifles, but as you probably know, it is no longer being made, so depending on how much you have, I dont know if it is a powder you want to invest a lot of time in. However, I have used 19 gr of 4759 with  405-440 gr bullets for a great low recoil offhand load, and 23 grains for a match target load. It is my best powder for 45-70 (and 38-55). 
The LYman Cast Bullet Handbook, 3rd Ed, copyright 1980 lists a starting load of 18 gr and a max load of 23 gr with a 420 gr bullet. Those loads a listed for the 1873 Springfield. Hotter loads are listed for the 1886 Win and1895 Marlin,  of course, but I never felt the need to go there. 
I hope this helps.
Good Luck, Joe