Jon
So a hard mask ie pressing down tape will get you the best results. What I do normally is spray the base coat over the tape so that if any paint bleeds ( which it will) it bleeds via the correct color. Then I paint color #2.
A soft mask ( this term I learned for a FB airbrush group) is a term used when you mask something but don’t want a hard line but rather want to feather colors together. Hold a piece of paper a few inches away and spray at 90° you’ll get some overspray but it will blend in as it “fades”.
What I did for this building was tape like a hard mask but only did the tops of the battens. I got overspray like I expected on the board sections of B&B, but once I gave the building a wash of black for a base layer of weathering it just about disappeared.