How far are you going? How much are you going to shoot? A pound of powder gives you 100~70 gr loads. That is about 2-1/2 to 3 pounds of lead balls. Actually, that is a lot of shooting on a trek.
It is hard to improve on the metal one pound cans. If you want to conserve weight, I'd say eat a little less pizza before you start out. If you dont want your nice bright red and white Goex cans shining, I'd say take some paint remover and take the paint off down to the metal. However, by all rules of common sense and safety, the cans should be labeled as to what they are.
I think you are in a generation gap. Better just take an extra can of powder with you if you think that you will need that much or, make plans for a trusted friend to check in on you at certain points with extra powder and lead balls if you anticipate that need. There comes a point in all of this where modern rules and safety and politics
overshadows period correctness. If anyone asks, just tell them that you just passed through Bents Fort, and that was all the powder that they had.
B