I like Trail Boss for light target loads in my 38 and in my 45 acp. I have shot several thousand rounds and shoots well and it is a powder you can usually find. Have not tried in my 45/70 but a lot of people do use it.
I use Kaytee Walnut Bird Litter from pet smart about $1 a lb and Nu Finish car polish. Cheap and works great.. Use about 1 cap full per tumbler load.. Make sure you put the nu finish in the tumbler and tumble about 10 minutes to mix before you put your brass in the tumbler.