Good luck Pete with your shocks.
Sounds like good advise about the shock oil. It would be wise to find out what weight oil is in there "From the factory". Next, find the affects of the available oils (Lighter vs. Heavier). Then you would have a baseline from which to work and a direction to go. I would bet the shock oils have unique characteristics that would be good to know.
You stated you had adjusted your air psi and did not find the ride you wanted. Sorry that didn't work for you. For me, at 220, I found the recommended psi way too stiff. At 40-50 psi two up, it was rough! When I ride solo, I go with just 10 -15 and two up at 20 psi. That may be too low for some bikes/riders, but that gets the job done on my '11 RKC.
Good luck on your adjustments, let us know how it goes...