This is a lovely detailed painting where the subject and composition are excellent.
It is not necessarily best to create a B&W rendition to use as a Luminosity layer on a coloured photo.
I've found a way to adjust the channels, for tone, and be able to view both the b&w and colour renditions at the same time.
I never followed up on the perspective issue of the earlier painting, so I did a wee experiment with an uninteresting shot across the field.
Hover to see what I mean.
I also took a number of telephoto shots and ran them through AutoStitch to create a panorama, but the program put them back into the above perspective!