When two up and pulling my trailer, I keep it all the way up for better ground clearance. My preload adjuster does nothing until #6 appears on the dash, so technically my maximum preload is 19. Yes, I still scrape in a lot of turns, but that's the nature of the beast between my ear lobes. :lol:
Next Spring I'm converting my bike's suspension to Traxxion, and I'm sure that I'll be selecting a much lower number with the new stiffer spring and shock.