FWIW, I've got his 'n her Pro-Pad inserts installed in the seat (H-D R/K Classic Touring seat..NLA, but I have a BNITB spare) on my FLHRCI. I had them installed at Sturgis in '06 by ProPad's upolsterer during a "Rally Special" promotion. The stock MILSCO seat padding was too soft after about an hour, and your butt sank to the seat pan. The Pro-Pad inserts aren't hot in the summer, nor cold in the winter and they kept the "stock" seat look and made the seat much more comfy and much more suited for the long haul. Their proprietary leather seat was mounted on a stool and not only looked great, but was extremely comfortable as well. I tried everything BUT their top seat pads, but can't imagine they're not comfortable. The cost was not prohibitive either. Highly recommended!
I've used the H-D P&A Hammock suspended his n' her's heated seat on my last two baggers: "11 FLHTK and the '13 FLHTCUSE8 (standard equipment0 and they are very comfy, albeit extremely pricy, as well. Can't beat the heat!