Thank you. Thank you all, encouragement is greatly appreciated.
It's a work of passion more than a work of patience. After all, this is "my world" for over 20 years. Still, the perspective of needing months at the current rate of production to have this finished is pretty daunting.

As for the grayscale version DEM... I've played around with it already but it's not so simple. This look gains from the mixing of layers and "partially" selected pixels. When I use selection to make new layers, in grayscale, there's a lot that goes awol. I am playing about with the idea of enlarging the finished heightmap 4x, then grayscale it, then using wilbur to soften/erode/fill the blanks. But, as I said, I think that's a far ahead, not an immediate issue.