Svabo: Perhaps what I have done to my 2018 ATAS any the reason for it will be of some value to you. My bike is set up with Tusk panniers on Givi racks, has Heed bunker bars and a few other minor things that add to the weight. it weighs in at 601 lbs full of fuel and with tools loaded in panniers (probably more tools than I need) I weight 225 lbs in riding gear. With the shock pre-load at the full 35 clicks the sag was 42% with a target of 30% or so. I shipped my forks and shock to Cogent Dynamics in North Carolina and they put heavier springs up front, a heavier over-spring on the shock, and machined a shim for that spring to accommodate a little more weight. I now sag at about 32% with the pre-load at 20 clicks, leaving me 15 clicks for baggage/gear. I do not worry about 2-up, and actually removed the co-rider pegs as they were one more potential to catch my calf with a foot down and break my leg. My Goldwing is sufficient for the occasions when my wife wants to go along.
I guess the translation is that a suspension that was designed for a 150-lb rider is going to to need some "beefing up" if it is going to accommodate some of us over-fed westerners, and that would be doubly so for 2-up riding. Good luck.
GL1800A, KLR 650, ATAS, 1972 CT2 Cessna Skylane
Fly low, fly high, but fly!