See CapnVape, as a meds user I would really think that the PD's design, including the specifically targeted "vapor zone", is in fact perfect for your situation. In many ways it is the PD's greatest achievement and most staggering hurdle, but it's no fault of the PD itself...merely the burden of the user. What I'm referring to here is the fact that the better the bud, the better your outcome is going to be with the PD (my
of course, but it's based in experience). On the surface this seems pretty damned obvious and logical, but the obvious part of the statment is not what I'm interested in so much.
Of course better, more carefully grown/processed bud is always going to give a better, deeper stone, and one would reason that a medical user has better access, or at least more license to seek access to, better quality bud than the avg. street user who must risk growing, if situation permits, or simply take what he/she/they/it/whatever can find. So, either grant me that as true or correct me of my prejudice, but I would tend to assume that most med users have access to better material (and I hope this is true as well, because those in need are certainly those who deserve the relief and the healing power of this plant). So then if it's true, if as a meds user you come into contact with more resin glazed, THC rich material than joe normal, and if you are indeed concerned about dosing efficiency...well I stand again to say the PD is the personal vape for you. I've been wrong lots, but let me drag you along further and tell you why I think this so.
The whole concept with the PD vapor zone is to reach and maintain a temperature range in which we see the vaporization of THC. So surely THC is not ALL you're getting in that temperature range and it is most assuredly not all that Cannabis has to offer--but if you're a meds user then presumably you're dealing with material that has good resin production and a higher than average THC content, riiiight?? So the PD's narrow heat corridor is perfect for high THC varietals. It's not so great for average or poor quality "shaky" street schwag. Not much resin to be found here, and although it still works it takes a lot more of it (making the PD less convenient) and sometimes higher temperatures (achievable with something like the SSV or whatever, but not the PD). For this reason high quality bud is PREFERRED for the PD, and the Vapor Zone is then seen as something which will only maximize your experience: it will ensure you're staying in the perfect temperature range to get those THC goodies, knowing that it holds that range as well as it does through such a variety of hit styles and intensities, it will allow you to dose that very effective high quality bud more efficiently--as I'm sure you can tell the PD bowl/stem is a relatively small does (which makes it harder to use with lower THC varietals--like I said, the greatest advantage and the greatest hurdle..)--and as you've mentioned, one of the great benefits of this vaporizer is that it's safe enough to be left on all day for constant, any time usage, and the small dose packets have the oh so pleasant side effect of NOT succumbing to the vanishing returns scenario of the death of big bowls...every hit, except sometimes the last hit on a tube (but really even then the PD has NEVER been foul or even slightly "popcornish" during my usage) is TAAaaaaasssssSSSTY!
This vaporizer just keeps getting more fascinating, as well. Something I've long thought, I doubt actually that any PD owner has not come to this conclusion just through using their own PD, but it was recently articulated here so it's worth bringing up now. The fact that you're mating a SS bowl with a SS port, both of which conduct heat from the internal heat source (the port gets hot enough that you don't want to touch it with your unguarded fingers) adds an element of conduction to this convection vaporizer. It's never enough to even come close to scorching your herbs, but it does aid in warming that small mass of herb material in the bowl evenly and thoroughly, creating for no real "weak spots" in the air/vapor stream you actually pull through the tube (in my understanding/theorizing). I actually like to hold my stem in the PD unit itself, with the SS parts mated, holding the unit upside down with the stem and unit all in my right hand (this has become really comfortable and second nature, and the PD is one of those things I just USE without thinking about it now...very routine/habitual). I hold this for a few to just let the bowl and the herbs to warm up then after my first hit I just always return the stem to the PD after I'm done drawing on it, and thereby let it heat up again. I have just developed a rhythm in this sense. Once you've taken your first pull, there's no need to really worry about holding the unit/stem at a downward angle or right-side up (stem on top, PD body on bottom): the herbs aren't moving once you're liberated some resin
!
Anyway man I could seriously go on about this thing for way too long, so I'm going to shut up in the hopes that I don't sound like I'm shouting from the rafters yet.
I really think you'll enjoy this soon, and then I can sit back and let you do the mad ranting for a while perhaps?? Heh
I really, really want to! ) but deep down inside, I know he would be the most pleased with the PD.
some of the comments are very touching. 
Same goes for anyone else I missed. Hard to keep up with this crazy forum you know.
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