@Fehlindra Been a while since I played with PP, been ZO exclusive since 2011. Don't know if the switch requires magnets for slalom or not. With a PX of 0 it does nothing, above that it adds the setting as a percentage of skier weight to rpm. I went with a 20 so would get 40rpm added when engaged (200lbs skier weight, I lied, better for opener. Did sound like titanic going down at the ends in tournaments though beep, beep, beep,,,, whole lotta beepin going on.) I recall I could feel it on the pull out, before the gates/magnets, so would assume magnets not needed.
I had a single line display that worked with the switch, upgraded to multi-line when I put Stargazer in that boat. So single line head worked, but did have new enough rev for KX -, n, + or ++ settings.
One of my favorite quotes from a big gun back in the day responding when asked why he skied ++, "because there isn't a +++!"