I lost the shroud on a couple solar yard lights and found Bruce's design simple enough to copy and tweak in Tinkercad. I scaled my version up to 3.5" ID, shortened the shroud length, and added three pegs to secure a protective LED cover that the original shroud held on. I also removed the inner ring groove and added dimples for screw washers.
I recommend PETG since it's going outdoors. Supports are required, and it also needs a screw to hold together. Screw size doesn't really matter, I used an M4x18 because I have a lot lying around.
Took about two hours print on a MK3S+ 0.6mm nozzle, in black Polymaker PETG.
The author remixed this model.