The donated plastic shields I received were much thinner than the 0.5mm PETG that Prusa's designs were using, so the support/"chin" piece would just fall off of the plastic.
So, I modified the support piece so that it would fit on this thinner PETG and decided to update all of Prusa's models in order to include this thinner piece in all of the stacked versions as well.
NOTE: The ONLY difference in my files here are that they are designed to support the plastic I received from https://www.pwfaceshield.com/ in the US. These sheets are 12x8.5 inches (approximately 300x216mm) and 0.25mm thick.
I included a STEP file for the thinner reinforcement piece in case anyone wants it
All the files in here are EXACTLY like Prusa's files, just modified to support this sheet size. This means that the "complete" files actually print with Prusa's super-fast settings.
If you use the 3mf files as-is, just know that they are tuned for the super-fast Prusa settings (except for the template, though that would probably work at that speed too)
The author remixed this model.