Kangaroo,
I am 6'05", evenly proportioned, and have a 610xl with straight bars and it fits fine. I have a 12cm stem and could probably go a bit shorter. You won't have a problem. I did have a 610s and it was just too short, with drops, plus the 73 degree ST angle didnt work well for me.
Pete,
I originally was going to go with drops and was steered towards the xl which surprised me I just didn't believe drops would work with such a long TT unless a person really likes to be stretched out. But now that I have it, I think it might. My road bike is about 59cm from the tip of the saddle to the stem clamp and my xl is 62cm with the stem horizontal. Going with a 10cm stem and mounting it with a positive rise would probably get me pretty close. The 71.5 ST angle actually gives you a shorter effective TT length which helps. Please let us know how yours fits.
Thanks
Paul