Simple NWPP mask
Using the Smart-fab NWPP I now have, a "Fabric CT" that I quite like.
One layer of 180 TPI poly-cotton. Two layers of the smart-fab. Those two NWPP layers together are 84 gsm. Also shown is the magnetic clamp I use so I don't have to use a pen on fabric or pinning. I used to make 40 at a time (on a string) with this in May 2020 before mass supply of cloth masks kicked in. This pattern does mean some snipping after sewing, but it's all fairly easy.
My other higher-filtration NWPP mask - https://fu-cv.blogspot.com/2021/03/nwpp-version-of-ragmask-max-very-quick.html 
The Fabric CT mask, including construction videos (out of date now - no retainer needed anymore, and a magnetic clamp used is now used for quicker construction) - https://fu-cv.blogspot.com/2020/05/building-mask.html
This is more wasteful for the sheets of smart-fab that #1 is. I can get four layers per sheet with #1, but only three layers per sheet with this pattern. When the snipping has finished there's quite a bit on the floor, but the mask is smaller on your face. That means that the edges are a place for air leakage. Have it loose fitting or draw an extra sharp breath and you can feel air coming in unfiltered at the cheeks. That's why N95 has classically not allowed year loops - not tight enough on your face. I think this mask might be able to take three layers of smart-fab and one of the outer cotton (low TPI) and not be forcing ingress at the edges. Any more than that and it might making it less useful as high filtration.
Next up - chuck in the washing machine on a hot wash. Then dry .. and report back.