I used to own an early PM(VM)4 with Delano pickups. I was never happy with the interaction of the P and MM pickups and I tried a lot of modifications including wiring the MM as a single coil. I didn't find an enormous difference between single coil (front coil) and in series, as the MM is set quite a way back towards the bridge in comparison to the TM4 I also owned.
I also tried fitting a Haussel alnico MM (and various P pickups) but again didn't find a radical difference given the positioning of the MM.
The large pole Sandberg P's interact better than the Delanos, I felt, but the bridge pickup made less of a difference.
Not sure if this helps!
It does thanks!
So how did you end up resolving your disappointment with the PM? Did you go with a completely different model?