Update #2
The model I'm using is on Thingiverse at [Hexagonal tile with Clip](https://www.thingiverse.com/thing:5955368)
So, I am pretty sure that I won’t easily get much better than my final effort.
Be warned this is still very much like frosted glass except for stuff which is really close to the pane.
There is no difference in the filament used. All are using the 0.4 hardened nozzle.
slow : sparse/internal solid infill and top surface set to 100mm/s
Top Row, Left to Right (0.16 Optimal)
[1] This is a default monotonic print
[2] This is a quick print with the settings mentioned above.
[3] This is the same print but using ironing on all the top layers.
[4] This has the same settings as above, but going slow
Bottom Row, Left to Right (0.08 Extra Fine) - all prints are slow
[5] linewidth 0.45; top shell layers: 2 /bottom shell layers 2.
[6] linewidth 0.40; top shell layers: 2 /bottom shell layers 2.
[7] linewidth 0.60; top shell layers: 1 /bottom shell layers 1.
[8] A miracle! The filament is now completely invisible!!
The lighting isn’t great, but 5 and 6 are definitely duller - thanks to the two crosshatched layers that they have. 6 was noticeable worse than 5, not that you can see it here - so I increased the linewidth to 0.6
So, the final result is … not too shabby.
The settings are as below (all other settings are defaults).
