I too got rid of the stock seat within a month of buying my bike. Looked good, but no support at all. I ended up selling it and the sissy bar on the Marketplace here.
I went with a nice, orange/silver flame-stitched Corbin DualTour with rider and passenger back rests, and a matching TP backrest for when I have the TP on. I got lucky and found it in the Marketplace here. It's GREAT for me, but not good at all for the BSR... the rear seat is narrow, hard, and slopes forward, which causes the BSR to slide forward.
I also have a Mustang Super Touring Wide Vintage seat, with a matching Mustang TP backrest for when I have a BSR. It's good for me (but not as good as the Corbin DualTour) but it's GREAT for the BSR. The rear is nice and wide, amply padded, and is flat - as it should be. My BSRs love the Mustang!
Ken