Painted buildings can be successfully included on a backscene in perspective, but because the scale layout foreground has a different horizon datum to the artificial backscene illusion, it's the sharp transition between the two that sometimes gives trouble. View blockers can help to control the observation angles in some cases, but middle and far distance buildings look great in perspective. Why struggle, just leave yourself a bit of depth for a 3D backscene portrayal in the foreground, it's by far the most convincing method of gradually easing the eye away from the lineside and to the distance, and you can include plenty of interest and character to the locality in the process.
(The feint blue horizon datum in the 'Generate a Panorama' colour pic corresponds to the far distance. and all the different vanishing points are registered along it).
On your profiles I noted you have a website and think I managed to see the unit you are talking about in the gallery, looks very nice.
What is the approx cost for a medium weather on a Heljan Class 26 plus add detail at one end