6'11"? That's tall! I'm 6'4". I got custom seat brackets from Jim at
MotorSportSeats.com. They lowered my Sparcos and moved the mounts back. I can still move the seat back more. That should help with leg room. Seat to top still could be a problem at that height. I have a little room with the seat setup (enough for a helmet) and I have a long torso.
Depends on what he is comfortable with.
There is also the full custom route. Check out some of the builders here, with all that skill I bet they could work up a solution.