I have to stop the painting of all constructions to fix up some bad Houdini generation of the vertex painted meshes, I have noticed, and you can imagine fix up about 39 constructions one by one, since the previous ones were ok by manual fixes. But now it's ok, also I found some nasty bug to triplanar material where I look…
I'd take some images of painted surface and put them over the wood layer, probably 2 or more layers of different colored paint to really make it look worn and painted multiple times. First I'd marquee select each boards worth of wood and flip it so that the paint pattern doesn't continue from one board to the next. Then…
Updates! Continued the painting. Progress can be seen below. This is primarily a painting and much less a matte painting, the only photo resources I used were a photo of a brickwall that I took long ago and a metal surface, rest was painted.