I have the exact same trike as you regarding bike and conversion year and I'd also be interested in hearing about how to adjust the suspension just for information sake.
As I can never get under my trike as well, my installer and friend/mechanic at the dealer also verified that my suspension is set at the softest setting. I rarely ride two-up but have always had my rear tires set at 20 psi and just recently brought my front tire down to 38 psi from 41. I can honestly say that I haven't experienced any rough ride conditions regardless of the road surfaces.