"The stem seems way too loose in the unit to do much good." ???
Ummm..........the stem is supposed to be loose in the unit, and a loose stem has been doing very good for a bunch of us for a very long time, so I believe that the above statement isn't very accurate. Needed to mention this for any others that may be new or prospective users of the PD.
Regarding your statement that you get 5 or so good draws and then dump the ABv into a LaunchBox and being able to get another 5 hits or so is baffling being that the PD only holds about 0.025 gr. to begin with.
Ten hits from that amount is quite extraordinary.
Be that as it may, your PD should not be leaving your bud very green. It should at least turn your bud to a nice golden brown.
First question is, how long did you leave your PD on before hitting it? Takes about an hour to reach full operating temp. Secondly, while the PD likes to see a pretty fine grind, you don't want it ground as fine as you would grind it for the LB. Also, make sure that you don't pack the bowl too tightly. You want to be able to get a draw out of it without being too restrictive. Also, for many, they like to have their bud very dry before loading up a stem. Not for me though.
All vapes have a learning curve, and in this regard, the PD is no different. Experiment with how wet or dry your bud is, the fineness/coarseness of the grind, how much you pack into the bowl along with your draw rates.