I feel that the low profile 30 slicks have more traction at similar diameter to the old 30 slick. I think the large heat cycle to cut down the old tires removes some traction, however over long stints, the old 30 seem to maintain traction without changing quite as much.
those PN20 still work? I remember the PN18 which was one of the best front tires to be on...
The new low height 30 slicks are a lot stickier than the old 30 slicks, even before cutting the old ones down. You can just feel it. Plus when mounted on 20mm rims, they are the perfect thickness, so no need for truing. I didn’t notice any change in traction over the run, but I’m not nearly perceptive as you are EMU. Unfortunately I don’t think they will be tall enough on 19mm rims which is what I mostly run.