Soon after I got the '09 SERG last year (which is factory "lowered" 1" in the rear like yours), I upgraded to the HD Premium shocks (standard on yours). Although the HD P shocks were an improvement over stock, (I, like you, prefer ride quality, although I will scrape the boards once in a while) I was thinking that they should be better, played with adjustments ~ not that much noticeable difference. The left shock blew a seal after only 200+ miles, Dealer replaced both, ride about the same.
The big difference for "The Ball & Chain" and I was when I had the HD Premium Double Cartridge Forks installed and adjusted the shocks to work with the forks and everything settled in.
Now the suspension is everything that I want in a sport touring bike, Great ride quality, smooth, supple, almost no brake dive, great cornering, no wallowing, good firm feel (not harsh,as some other Popular suspensions, just right for me) And (most importantly to us) when the suspension does bottom out on those unavoidable bumps, it doesn't drive our a$$holes to our necks.
Over many years of riding I have learned that when it comes to suspensions,
the front and the rear have to play well together.