Here is my first take. I didn’t use HDRMerge because I had problems with it. As usual, I took the low-level approach to processing. The scene itself is so interesting that I decided not to add much creative flair. Hence, it may be a bit bland for your tastes. Enjoy!
1 PhotoFlow → linear Rec.2020 without clipping (+EV only).
2 gmic → interpolate bad pixels → brighten (copy).
3 enfuse → recover contrast in sky from originals.
4 gmic → discard alpha → interpolate bad pixels.
5 hugin (middle frame as anchor) → CPFind+Celeste → geometric (all) → photometric (ldr,vwb).
6 gmic → discard alpha → interpolate bad pixels → brighten.
7 pnmclahe → moderate contrast enhancement.
8 gmic → recover chroma → resize → sharpen.
PS As you can see, I solved the artifact problem that I asked about earlier. My problem was that I clicked on the Create control points more than once generating an unhealthy amount of control points!
What I am still not satisfied with is the horizontal stretching at the left and right extremities, and also the cropping compared to other submissions. I guess that would be due to the centre frame being the anchor, and also the fact that I am only using 3 frames.