Trainwhiz,
Unexpected that you are interested in steam. As you know, there's a great deal of lore surrounding them. Another kudo, you can compose & spell!
Weathering; try dry chalks, if you obtain the kind that do not have an adhesive mixed in them, you can wipe off mistakes, or lighten your coating. If all you find are those with the adhesive, a sponge/cloth/cotton ball can be used to wash them off, which might then produce an interesting weathering effect. I have some unpainted brass 4-6-2s SF
Cl 3400 protos. Under $180 + post. If you want more info please contact off list.
DM&IR-Yellowstone man. I am considering disposing of one of these, however, it is a B&O prototype. If interested, contact me off-list. It is well under $500.