I had found 4198 to be a tad slow. It was discovered by another member shooting his 1895 cowboy (I apologize Kris, I do not remember your Avatar name) that aa1680 produced the highest velocities for this combination. Since I don't have my hands on your rifle, I would say 58 grains of 4198 would be a good place to start. You should run out of room before you hit pressure.
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Be careful with your cartridge overall length if you're using a Marlin, they have a short throat. If you crimp in the top Groove you will Jam into the rifling. Your brass will have to be trimmed .070 of an inch to line up with the middle of the top PDR band Valley and then I'm not sure if the FCD will crimp properly on cases trimmed that short.
The issues I've just covered are one of the main reasons why I went to a 45-90 CVA. And of course the other one was to hit 3K with a 45 caliber bullet
Hope this helps