Lobby when the time comes to respring the bike. You might have to get the current springs measured for stiffness. I've never seen a spring rate chart either.
It kind of buggs me. With the old preload. One could load the bike right up to it's limit just by changing the amount of preload. It's not the ideal way of doing it. But it worked.
Now with just three settings, normal, comfort and sport. I don't see a way that a person can load the bike to it's rated load limit.