That makes sense.
Keep in mind the goal here - don’t spray particulates, so anything doesn’t doesn’t leave a gap and trips the mouth spray will do. The next goal is a not breathe in other peoples spray, so you want something to not collect moisture. Also, you want to breathe so moisture will clog whatever passages there are in the mask.
I’d look for something that doesn’t retain water and fits well. If you can keep the moisture from accumulating, you’ll breathe easier and stay healthier. Probably one of the better materials out there will be Olefin (Drymax, Thinsulate, Polypropylene), which is what they make super thin running socks, thinsulate insulation, good N95, and some surgical masks out of. Maybe cut up a Drymax brand sock and have someone - like your drycleaner- make a custom mask for you - https://www.amazon.com/Drymax-Sport-Unisex-Running-3-Pair/dp/B014LW32RA . You might also want to make the straps out of old bib shorts (hell, just wrap old bib shorts around your face).