On my 2015 gen1, my pillion and I used Airhawks. Uncomfortable seats, they helped.
On my 2018 gen3, we both felt they weren't needed. Seats more comfortable.
For my recent roundOz ride, I bought a Cool Cover for the expected heat. It was too cool on the cool mornings, but an unexpected benefit was the extra all-day riding comfort it gave. I still had to jiggle my bum and stand up occasionally between fuel stops, but it was better.