Still experimental, but design has stabilized to the point where we wanted to publish.
All of the gaskets ought to be printed in TPU (recommend full top/bottom layers, 85a is best).
Other parts to be printed in a hard plastic. If you are printing the Buck in PLA, we recommend you put it in the freezer in between vacuum forms or the geometry will quickly degrade. We used a Mayku to do the forming, with PETG sheets of 0.5-1.0mm thickness. Waistband elastic of 1/2 inch thickness was used for the straps. For the filter material, we have been using P100 simply because that is what is available, but other material would work too.
The blow-out valves are optional depending on the need.