Hi.
Since I complain in my head that this forum is not active enough, here's my contribution...
I am researching ways myself about making masks with paper, suing moulds. I've had a general reply to my very detailed questions, answered by a master mask maker in Italy.
For my materials question, she told me she uses a strong cotton paper that she pushes into a negative mould made of plaster.
No mention of a brand or thickness, or even of a release agent.
So i tried on my own, but not in a negative mould. I tried over my positive form, because I did not know yet how to eliminate the folds and wrinkles that would occur in the negative mould.
So I played with the folds, since I could see them on the positive, and the folds are part of my designs. I tried with Arches watercolor paper. One medium thickness (less than 140 pounds) with carpenter's glue (yellow wood glue) is very strong, but will need scealing against moisture before painting. This glue softens with moisture.
But once scealed and painted and then varnished, my masks are nearly indestructible!
I tried again with a much more affordable cotton paper from a local paper maker. Easier to tear once wet, but if you are careful it feels just as strong once it has set.
The trick is to use a strong, long fiber paper.
Forget about regular wood papers. Try rice papers, I'm about to do so myself, as I was told their fibers are stronger than cotton fibers...
It is not a matter of brand, it is more a matter of kind of paper to use.
Of course, experimentation is the best learning tool.
Also, try draping fabrics over postive forms.
I do this all the time, and the folds teach me a lot.
Hope this helps.
If you have a way of eliminating the folds that would occur while pressing the paper into a negative mould, please share with the world.