Have you considered using "tear offs" for the helmet faceplates like race car drivers do? These are thin layers of plastic that can be individually torn off from the helmet visor as the get dirty / scratched. Cheap and effective.

It will be very interesting when the MS starts trying to use pressurized suits. We have had Russ inside our russian Sokol suit with pressure a couple times now, and movement is a LOT more difficult. On the plus side, it is much more comfortable when pressurized, because the weight of the suit is off of your body, and you have a constant internal air flow. There is a fair amount of engineering in even these type of emergency suits, let alone EVA suits, but it isn't out of the question to have some people start experimenting with homemade pressure suits.

John Carmack