For those that don’t have a laser cutter, this stencil will allow you to mark out the top and bottom holes along with the corner curves. Align it with the top of your clear sheet, draw or (carefully) cut around the corners and mark out the holes for the punch. Repeat at the bottom.
This uses the imported configuration from Prusa’s RC3 Face Shield for PETG. Apart from: top and bottom layers were changed to 2 for speed and layer height changed to 0.3mm, again for speed. It could look prettier, but it’s a stencil! Total height 2mm. Approx 2hr 15mins on a MK3S.
(Design based on Prusa's Visor PDF drawing)
The author hasn't provided the model origin yet.