White Pass is 3 foot gauge correct??? Maybe the reason not a lot of standard gauge models made. I'd like a WP Alco in On30 myself.
Nice to see someone else repainting locos. Follow lee's advice....pretty much the same as I do but I use Tamiya 1/4" tape for the separation line and low tack wide masking for cover. Burnish the tape with your nail. I use my digital calipers to make line guides to keep things lined up.
Good luck!
I used Tamiya tape and my calipers to lay out this paint scheme....