recommending PETG for flexibility (you know how many glasses you broke right?)
increased infill - like 50%
3 perimeters
test the length first to choose the right that fits your head
use mirror in slicer to print the other one to the pair (or use 3mf or gcode)
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Assembly (to the glasses):
use short 1.75 filament piece and insert it into hinge
if filament is too loose, you can increase both ends sizes for example with putting something hot on to it, so it melts partially and creates larger heads