You mentioned long haul truck drivers in your post, so I will tell you what I used with great success for long periods of sitting.
As a OTR driver for 40 years, I have tried almost everything to ease that sore butt syndrome.
I worked for an aerospace company and we were always guinea pigs for a lot of stuff. Some worked and some not so much.
One day an engineer from the Space Program came along and said that he had a solution to fatigue and that sore butt syndrome we all had from long hours of sitting in the cab of a truck,and that they were using it for their Astronauts and Pilots with great success and he wanted to test it out on us.....OH WHOOPEE.
Ya ready for this??
Sheep Skin seat covers......
As a full seat cover they were great but a little warm at times. So in the summer I just used the bottom half. I never went on another trip after that without one. I have logged a few million miles and this is the best seat cushion material I have ever used. You will see A lot of people that are confined to wheel chairs use them.
That is my story and I am sticking to it.........:B