I don't have any of the new P's, rather, I own the older ones.
IMHO, I'd do something Carl doesn't recommend doing.....I'd tear down both reels completely, including the bases. I'd degrease both reels and put on some new Cal's grease.....all screws, gears, bridge plate, bridge sleeve etc. as well as between the ss and aluminum parts. Ensure that all screws are tight. Also, degrease the bearings and put on a drop of Speed-X. Adjust left bearing cup as necessary.
If you really wanna go nuts, get some 2000 grit sandpaper and get the end of the spool spindles and the inside of the pinion gear.
Since I don't own any of the new P's, I can't personally comment on the fiber washers but I have read a couple positive things on this board. I do use the HT-100's and have nothing but positive comments about them.