Thanks for your experiences guys.
Okay that makes perfect sense pgomena... regarding oxidation and using ratio to combat the useful life of the developer although I don't think I'll ever need more than 14-15 minutes.
I haven't used PMK with sheets as I use trays and don't want my hands in that stuff for a protracted amount of time.

Im using it mostly for 120 and I think I used it with some TMX in 135 awhile back.
I see people mention they avoid 135 with it but I thought half the idea was for grain masking.
I just souped some Trix 400 for 12 minutes and although the negs aren't too contrasty I would definitely want to cut back in a situation where there is a large sbr.

I'm really liking the tonality I'm getting so far with Trix in 120.

edit: thanks for that link payral