I can only speak from personal experience, I'm 6-2' 205lbs I can fit in the first generation Mazda Miata no problem but with the top down the top of the windshield is in direct alignment of my eyesight I either have to lower my head down below it to see out or put my head above to see over it as if I was driving a clown car in the parade. and of course with the up I have to crouch down to look under the top of the windshield.
Either way I find it very uncomfortable and dangerous to drive, I do not have this problem with 2005 and newer Miatta's.