I put the mustang Regal Duke on mine, It was a good step up from the factory for the rider but on long trips you seam to soak in the seat more than the Wide Touring seat I have on my 750, The wife prefers the touring seat as well s its wider
If I got a new seat now I would probably get the touring seat with backrest, When riding long trips solo I have a barrel bag strapped to the pillion seat and it gives great back rest nd I can travel all day and still have no back issue
I have had 3 different progressive shocks on my bike, the first set were far to stiff and never settled in.... hard on my back 412 12" so after a good while an still not softening I put the shocks from my 750 on, 10.5" std 412's and the ride was far better but my exhaust bracket started to scape on hard cornering then I got some 444 12" shocks and they were a little firm to start with, 2 up perfect and if you do hit a big hole/mound they don't bottom out hard like the 412's.... and after 6 months and 8,000 miles they are sweet one up and wind them up to the first line for two up, bit more if a lot of gear
I also fitted progressive fork springs and changed the oil, I played with the pre-load a bit and ended up going to std weight oil and the bike handles like a dream (we have some pretty rough roads so the suspension needs to work well)
the Regal Duke seat fitted
I did redo the rubbers its sits on, they are multi fit and didn't sit quite right for my liking so I removed some of the rubbers put plastic on the frame and put a load windscreen glue where I wanted supports and fitted the seat, removed the seat and trimmed the glue (sets like rubber)
the glue I used
http://www.bostik-us.com/sites/default/files/70-08A_0.pdf