When I acquire lead of different types, my approach is to first melt the lead of each type in a smelting pot and flux then pour the cleaned up metal from the different batches into ingots.
I segregate the pure lead from range lead from linotype from wheel weights. Then I use a stamp to mark them as they will inevitable get moved around and mixed.
Then I can easily mix up a batch of a known alloy using the exact number of ingots of various types.
It's good to have some pure lead around and the lino separate.
Any scrap lead will work for 45 and moderate 357 loads. Hotter 357 will need a more controlled alloy.
If you use the shot for holster forming, keeping it as shot would seem to make more sense.
