My initial thoughts on the "Power Adapter" question.
Well, I've had a few stems now through the Walnut Zap with the 13.5vdc 1000mA Jameco adapter. So far I've tried the 12v naked, 12v double layer koozie, and now the 13.5vdc. All of these were observed using the same homogenized herb source, as performance varies based on quality in my experience. These are my results with MY Zap. YMMV.
12vac naked: 2-3 hits with exhaled vapor, with the first being the richest by far in taste and texture. ABV is still noticeably green, but mostly light tan.
12vac koozie: 4-5 hits with exhaled vapor, the first 2 being the richest. ABV is uniformly medium tan.
13.5vdc: 3-4 hits with exhalant, with the first being very dense and rich. ABV is mixed brown/tan.
I need some more... ahem... trials, but I'm really liking the 13.5vdc. Not too worried about 24/7 with it, as the enemy of these things is heat, and they're left with koozies on 24/7 all the time. Mine would nearly burn your hand if you took the koozie off of it. If I lose this bet, I'm sure the resistor isn't all that expensive.
UPDATE:
Kind of hard to get a full rip on a fresh stem with the 13.5vdc. It starts tickling and I have to stop and wait a sec, or slow my pull even more. However, when I pull it off... Yeesh. The fog rolls out across my desk. Barely a second hit left after one of those. This thing is a beast! It'd be perfect for bongin'. It'd have no problem toasting the whole stem in 1 pull.
2nd UPDATE:
Too many trials...