I acquired the Korber #927 Brick Switch Tower several years ago when I was at York and finally found a spot for it on my layout and was looking for ideas on how to paint it and found this thread which dates back to 2015. The model is still available at Mr. Muffins's trains.
https://mrmuffinstrains.com/pr...7-brick-switch-tower
I liked the way the original poster, Brian, painted it, so I just copied it. I elected to put the four walls together first, then paint with a small brush. I used paint from an Arts and Crafts store. I made a few modifications. For the windows, I covered the backs using material from a poly folder: the Pendaflex Poly Project Pocket, Letter Size, Assorted Colors, 10/Pack (53296). Amazon has them, they come in a variety of colors including a translucent clear version. I use them at work so had slighty worn one to use. I also added a lamp over the door (got it at York, don't remember which dealer).
For the mortar, I used Roberts Brick Mortar. Jim Barrett had recommended it. I bought it years ago and only used a little of it. I was worried that it would have dried out, but only needed to be stirred (not shaken), and I was ready to go.
Its located on a new yard on my layout. The track is operational, still working on the landscaping.