This in deed is the biggest flaw I can see o PAX 3. They should try to find a solution how to fix the heating of the upper portion of material. Packing with the half pack lid is not an option for me since it created to short sessions. I tried to get around it by grinding away a part of the half portion lid in order to achieve an optimum pressure and oven size. However - the half pack lid is no made out of solid material! When I grin of a portion of material it broke and revealed a cotton or some fibre inside. I rendered it useless. I am not thinking how to attach another 3D screen to the regular lid without using any questionable chemicals. Such metal end of the oven lid would be optimal for the oven size and perhaps contribute to more heating in that portion. I am also still looking to buy a secondary vaporizer. I would hate getting into a situation where my PAX fails and I stay without a device. After my bad experience with Crafty I was ogling Davici IQ. The reports I read however turned me away from it. I am not thinking or ArGo but would love some personal reviews from a tobacco smoker first. Did any of you tobacco smokers order it? Another finding one might be interested in: I was looking for a tobacco grinder. Reading all the plastic particle, aluminium particle etc discussions plus not really liking the concept of weed grinders I started looking into manual coffee and herb mills. I made a jump and bought a Porlex Mini coffee grinder. https://www.homegrounds.co/porlex-mini-hand-grinder-review/ It uses a set of spring-loaded ceramic burrs - I reckon nobody can find any health concerns with those even in the event they would chip and end up in out tobacco. I am happy to announce that the results are great! I can adjust the roughness of the grind and tobacco stays in the jar so there is no annoying grinders emptying that ends up everywhere. Because grinding tobacco shows less resistance than coffee I skip the crank, hold the bolt and turn the whole body.