As you disassemble take closeup photos so when you reassemble you will have a guide to know what color wire went where and how each part goes to the correct place.

I've made my own "cheap" spray booth. Take a cardboard box open on three sides, then add an old box fan with a furnace filter on one side to "suckout" the overspray and fumes. As others have stated, don't paint in a room with a furnace or water heater or doesn't have out side air. I have a window in my basement and set this up so the fan is close the window to exhaust the fumes to the out side.

In the past have mixed black and silver to match smoke boxes. You have to experiment with the proportions to get the right shade. Let the paint dry before deciding on the the final mix.

Check the front trunks of the tender to see that they not only turn freely but they have some slight play up and down.  I had a similar issue with another steamer and found that the tender trucks were pretty tight: and that loosening the trucks allowed them to pass over frogs and tight radius without derails. -John