I can answer that for you. For easy casual riding by myself I run at 20 PSI. When both of us are on I use 30 PSI. If I have both of us and the trailer I use 40 PSI. If it gets really windy under any condition or I am riding 'twisties hard, I use 60 PSI. It is as stable as a rock at the higher settings. This data accumulated form the last 25,000 miles of riding under all the above conditions.
I set my progressive shocks on the firmer side (always) and run my air bags at 25-30lbs for me and 40-45 with the boss on board (She's 130lb.)....I hope? "cause if she sees this and I'm wrong I'll be twisted into a pretzel and the only thing I'll ride this spring is an ambulance to ICU :22yikes:
I use that for both, and some times run it up to 40 or so if I am getting a little zealous, and mama is about to tare the handles off the sides, but she is getting use to some of that, now that I am slowing down.