Personally I’ve found going high contrast works very well at the scale. Bright colors vs very dark grey and brown. Also picking out some details in opposing colors works well too. I’ve stopped using washes for my 3mm but you might have better luck, especially Brigade models 1/1000 buildings, they have rough surface that stain rather than emphasize crevices.
Really looking forward to seeing the finished product.
For small scale I’d agree on contrast and due to the size, would recommend a white primer plus going a bit lighter in color across the board as any given color will tend to look darker on a smaller piece. Keeping things as light as practicable will help any and/or all detail to pop a little better at table height,
I’m hardly an expert on Victorian architecture but I believe red or brown brick was quite popular.
Never wrestle with a pig. You both get muddy and the pig just likes it.
The resin warehouses turned out to be the worst of all the small scale scenery to paint. I tried base coats of good quality craft paint but the rough terrain just seemed to absorb it (obviously it didn’t but the textured surface made it cover very poorly. Eventually I just used Vallejo but I think most of them took 4 coats overall. The smaller factories needed 2 or 3 coats but most of the houses & smaller building seem to be managing with just 2 but all now using Vallejo.
I used a mid grey primer but suspect these may have been better brush primed with Gesso.