I'm pushing 6'4". I have the seat as low as it will go, and as back nearly as far as running against the back. I then put the steering wheel up quite hight so I can turn full lock without my knees being dangerous. Feels stupidly hight for a while, but does create a load of room!
Went on a track day in my brothers Elise once and was going like a rocket, then realised my knees would not allow me to turn right! No room between wheel and knee. My brother wasnt happy when we turned the nose in and went flying through the gravel. One of the reasons I bought a Z is because I could fit in.
Good luck and happy driving.