I finally cobbled together a HM on the breadboard with a Micro Damper and fired up the cooker last night to test the whole thing out.
* Micro Damper servo only, fan not even installed
* On a Large Big Green Egg, top damper slider closed all the way and the daisy wheel all the way open
* Attached to the BGE with a 1" npt nipple -> 1" npt 45deg fitting -> 1" npt nipple -> Micro Damper
* P, I, D = 4, 0.003, 5 per SteveCK's own settings
* Fan off, blower from 0% to 100%
It works great!
I ran the grill for about 4 hours, started at 225F, stepped to 275F for a short time, stepped back down to 250 for the rest of the test (my smoking temp range). It performed well, responding to step changes very quickly and stabilizing quickly, with negligible overshoot in either direction. (I'm not particularly picker about overshoot or oscillation as long as I'm +-10F of setpoint... I stayed within +- a few degrees most of the time)
So for the purpose of using it as damper only control, for low & slow cooks, on a ~18" komado style grill, it looks like this Micro Damper will work great!
I still need to test how hot of a cook I can maintain with this little guy without a fan.
I'm smoking a brisket tomorrow evening, I'll report how it did on an actual cook. Maybe I'll remember to screenshot the graph too.
Thanks again, SteveCK, for the Micro Damper. And Bryan and everyone else involved in the HM project.