For what it is worth, here is what I have found after 20 years of searching for comfortable seats, and finding the solution some 15 years ago.
Have a look at your car bucket seats, in which I imagine you are comfortable for extended periods. See how wide they are, and probably with a raised section on each side. This provides support under the outer thighs. This is the same theory that companies like Daylong use to guarantee long term comfort......see photo below.
Now have a look at the Cannonball seat laid on top of the Daylong. It does NOT have that additional thigh support. This is why it works for some people and not others. Also attached are a couple of photos of an Airhawk Large, laid over both the Cannonball and Daylong seats. It hangs well over the Cannonball, and is not as wide as the Daylong. That is why IT works for some people and not others, as it effectively pushes air out from the centre to raise the outer edges and act as a type of outer thigh support. It is however, not as wide as the Daylong wings.
Even the likes of Ultimate, Mustang and Corbin do not provide support under the outer thigh, which is why they work for some and not others.
Sure, Daylongs and similar custom seats can be expensive, and perhaps ugly, but I can live with that as they give all day comfort.
I hope this info is of some value to those looking at sourcing aftermarket seats :dontknow:
Pete