I sent stems to all the testers with a couple low profile cup screens so they can give us some feedback. I used 1/2" diameter 60 mesh SS screen, this gives about a 1/16 lip around the perimeter of the screen. Battery life is not as good with the screens, maybe 20% less - that's a guess. Very hard to combust with the top screen. Extraction efficiency is excellent, couple of stirs does wonders. The stem can be emptied and then the herb sucked up and the top screen put back. After a few days you can push the bottom screen out and put the top screen in the bottom. This does keep the screen clean. @Alan has flat screens which offer less mass.