I had low expectations of these when I saw them printing. I did not think they would fit right, and they looked like they would break so easily.
I. Was. Wrong.
These things are brilliant. I made the ones for Inland/Esun 1.75 mm, and I am super happy that I printed a batch of them, because they are getting good use.
i don't think it needs infill. I just ran with the settings that were already set up in Cura at the time.