Fuma 2 ordered, expected to arrive Monday although Amazon are sometimes early.
Did quickly scanned some written reviews. With a little uncertainty it does seem a bit better than the Noctua U12A but not quite as good as the D15, although there isn't that big a gap between any of these. One review put it equal to a D15S which I didn't even know existed until now, just a single fan version of the D15.
Fuma 2 is rated at 137mm width so should be narrower than the borderline Lucifer I got in. It is unclear if they are counting the fan clips in that. Worst case I can bend them over a little more. It does look like the Fuma 2 is designed with a goal of high cooling performance while maximising other component clearance.
1 minute ago, Stahlmann said:
The U12A is about the best medium sized cooler you can get. It comes with 2 of the best fans out there, is only 158mm tall and cooling performance is about on-par with the D15. And the RAM compatibility is 100% because the tower is offset to the motherboard I/O area:
The U12A was on my shortlist, but based on reviews the Fuma 2 seems superior, and is cheaper for me to get.