Good looking, popular, and much sought-after though they may be, I have always found the flying buttress seats to be less than comfortable for long trips. I fitted a pair of early Recaro style seats (as fitted to an early 911S) made by BF Torino to my Super and like them a lot.
Turns out that Stefan at GTS Classics makes his own version that is a very, very nice seat. Now that he's turned his attention to flying buttress seats, I'll bet his version will provide perfect support for long drives. He's very careful about this stuff and his workmanship is first class.