My helmet is taken apart at the moment so I can swap out the retention band bit this is what I did. Cheap mesh mask, remove the headband (I think I cut it off) and weave a short band with with he head loc clip.
It doesn't need to be tight and it is by far the most comfortable setup for face pro I've ever worn. I also really like it because I can conveniently un clip one side to hit up my hydration tube or take a tactical smoke break.