I'm 6' and I thought my mate's 916 was a bit on the cramped side. AS others have said, it's bum up - head down so tends to throw weight on your wrists anyway.
I changed from ST4s to 749s because I wanted a superbike rather than a sports tourer. I found the 749/999 chassis to be more comfortable and whilst I was originally going to go for the adjustable seat/tank version (monoposto) I found the mid position of the biposto setup to be comfortable. I can (and have) ridden for several hours on it and still been able to walk.
Did a track day on it recently, and found that to be fine too. Then had the pleasure of riding Ruth's 996 back to ours which was about an hour. That I found to be cramped on the legs particularly and more weight on the wrists than I was used to. Due to long arms I could sit up and rest though, but I found myself stretching my legs a few times. Might have been stiffness due to the work out during the day.