Having more success with the nylon stem, at times though it could possibly be getting clogged? How can I clean the screens etc when this seems to happen (not able to get any hit). I have found with this nylon stem a very long slow hit does the best but I can still feel the heat getting to the mouthpiece so I have to slow down the draw even more. The weed appears I think how it should after being vaped and often I have trouble using the nylon stem for a 2nd hit because the weed is all but incapable of vaping. So far this is the only way I have achieved semi decent vape hits by just gently dropping grinder bud into the nylon steel stem then putting to vape fully waiting 7 seconds then slowly inhaling at slow pace, at times mouthpiece can't get too hot. I do still end up with visible vapor and possibly smoke as appears chatting while rest is mild brownish orange color
If you blow out the stem as soon as you're done hitting it (while it's hot) the screen will stay almost completely clear and clean for a long time. Doing this I only need to replace or clean screens every few months. If you let it cool in the stem it all sticks there but you can hit it again to get it hot again and then blow it out. If for some reason you're unable to do that you can push it out with a long thin dowel (or similar tool) and soak it in ISO.
Re: heat on the mouth - well you're breathing in super heated vapor (this is the point right?) so yes there's going to be heat unless you run it thru a water piece or something.
RE: 2nd hit on the Nylon Stem - this stem is made to be a 1 hitter so it's no surprise you aren't getting much of a 2nd hit since the material is vaped out at that point. Also leaving a stem on the vape for 7 seconds is excessive and unnecessary. The glass stems are ok to do this for a few seconds but you shouldn't do this with the Nylon Stems. Lastly, the slower you inhale the hotter the vapor is going to become, just a quick FYI.