Looks like the original question was already resolved
I was about to start writing about my experiences with Industar 50-2 and Helios 44-2 until I read the rest of the thread!
For landscapes you will almost always use f5.6+, usually around f8-f12, to get wide DoF. And at that aperture, pretty much all Pentax 50mm lenses will perform well! Older lenses might need a lens hood, because they have coatings that were not yet optimized with modern technologies. The f1.4 and f1.2 lenses are specialized towards low light and shallow DoF photos, which is not really what you need in landscapes. So buying the f2.8 super sharp, well-corrected 50mm macro was a great choice.
Regarding colour differences, this is not a big issue on digital, because AWB and PP usually neutralize this anyway.
That said, I used an old M 50mm f1.7 with a knock-off square lens hood, and despite shooting in a mountain desert, it still gave sharp, clear images. With a bit of PP, I got this:
Mount Teide volcanic peak by Stolpulus II - Photo 147079749 - 500px
The 50mm f2.8 will give better results than the decades old M 50mm, so I doubt anyone could complain about it.
I have seen your photos before, OP, and I hope to see more in the future, as they are very good and interesting!