I sat in the cockpit about three years ago, and one of the volunteer guide chaps took my picture from the port side. I have just checked the pic, and as a 5' 11" tall individual, the top of my head was about 5" below the top of the two side pieces of the ejector seat headrest immediately behind me. These obviously have to clear the canopy when this is closed, so my noggin would have had ample clearance from the canopy.
It seems possible that since I occupied John Farley's former working seat, someone has either raised the seat higher by its adjustment device, or added a fat cushion. Of course, I suppose it's also a possibility that despite your height and mine being only an inch apart when standing, you may have a much greater seated height than me. We are not all similarly proportioned, some have short legs but taller upper body dimensions.