I have been using PMK for awhile now and here are some of the things I have noticed
If you want a push developer , I would defer to a different developer.
The mixed Pyro dev oxidizes really fast... therefore I use two developers 1 liter each and split my normal time for trix into two 7 minute devs and keep the first bottle for stain.
I will go as high as 16 min for dev and as low as 10 min dev using combined times.
Mixing with distilled water is critical.
I have followed Mr Hutching's book pretty much and tend to think the tannin effect is the most important item for this developer.
For scenes with low contrast lighting ratios I do not see much use for Pyro over other developers
Different films stain different colour and starting balances when printing tend to differ a bit.
I will sometimes double the ration and go 20 ml A 40 ml B and 1000 ml water , this seems to give me a boost in overall density, not contrast.
Pyro works well with a rotary process and is a one shot only process .
I also believe that low light single source lighting really shows Pyro's capabilities.
I processed and printed a series of 8 x 10 neg's for Steve Evans that he was commissioned to photograph of the Distillery District here in Toronto before it was transformed into the go to location.
His exposures were all between 1 second and 1 hour long and these neg's and subsequent prints are IMHO some of the best I have ever done. If the room was lit by a bare bulb we could see detail everywhere and still see the filament inside the bulb with no halitation, or soft muddy highlights.