Bitubo rear shocks will solve your problems, IMO, IF you set them up properly. The seat is not the problem from what you are describing, it's the rear end bottoming out. Increasing the air pressure in the stock shocks will help the bottoming out, but will NOT improve the response of the shock itself, only the preload, which will stop the bottoming at the expense of response. Correct me if I am mistaken, but the RK has lowered suspension (by 1"). Looks cool, but the suspension has less travel. If seat height is not a problem for you (your inseam is 30" or more), you might want to consider putting the bike back to a full travel suspension.
Bitubo shocks have three adjustements: Preload (spring adjustment); compression damping; rebound damping.
The HD "Air ride" shocks are still POS shocks with an air adjustable preload. You've still got a cheap, low bid shock with an air bladder sitting on top of it. I have no connection with Bitubo, but just know from personal experience and the experience of many members here on the site that they are excellent. Give Dan a call at Traxxion Dynamics and he will fix you up. Then set the shocks up for two up riding from the get go and adjust the compression damping knob for solo, which takes about 30 seconds. If you want the ultimate solution, get the full height rear shocks, then have Traxxion install their cartridge suspension in the front forks, where they can also give you full travel on the front end. Night and day over stock, no matter the bike. JMHO. It ain't cheap to do the front end, but you get what you pay for in this case. At the very least, get the Bitubos in the shorter version to maintain the lowered look. I am confident you will be happy with this shock, and your wife will be as well. Be sure and tell Dan that you are a member of the CVO site.
Here's the deal with suspension: you don't know how chitty the stock HD stuff is until you ride a bike with decent suspension, then you will never be able to go back.