FWIW, I threw in a set of King Springs +50mm (standard front, HD rear) last week.

Runs 265/60/18s, newish EFS Elite shocks and shagged out OEM steering damper. Carries 65kg rooftop tent + ski and camping gear.

Drove 1000 highway km, haven't measured castor yet but she's a bit flakey at 100+ kph. I'll do another couple of thousand before deciding whether correction is warranted.

Ride is an improvement over OEM springs.