I hear ya, Doug. It's very diffcult to find any seat that fits properly in a GT6. And if you're tall and/or large, make that "impossible".
Carefully reconditioned stock seats are fine. Tear the seats completely down and replace everything with new stuff, they're pretty darn nice. Just please don't compare them to modern car seats, they're simply not going to measure up.
Miata seats don't fit either, I put them in and then took them out immediately. I'm too tall (6'2"). Smaller folks like them, sometimes.
Stick with the stock seats. It's not cheap to redo them, but it's well worth the effort and price IMHO. Nothing looks better, they're actually very attractive, even by modern standards, when redone. :thumbsup: