I shoot 4x5 and 120 using FP4 rated at ASA 80.
My process is very similar for both films and based on +/- N exposure system (Zone).
I use D76 or PMK developers in a Jobo Multi-5 tank with film reels on a Jobo CPA processor.
With the PMK, I split the development time in half and use fresh developer in a second development. For example, if my full PMK development time is 10 minutes, I develop for 5, pour out the spent developer, add fresh PMK, and develop for the remaining 5 minutes.
I used to tray develop PMK and my experience with it was that it really liked the constant agitation. In the tray the developer didn't aerate that much so it lasted through the full development time. In the Jobo, it sloshes around a lot causing it to oxidize very quickly. Using the Jobo and split development, the PMK seems to be very happy with the agitation providing very clean results in smooth areas like sky and fog.
Bill