Originally Posted by Bacciagalupe

Just to be clear... The bike is a very small part of the equation, especially when it comes to double centuries. Using a lighter frame might save you literally 10 minutes out of a 15+ hour event. See http://www.bikequarterly.com/BQPBPEquipsurvey.pdf for more details.

Rotating weight does have a little more effect than frame weight. I wouldn't worry about it, though, unless you know the course is going to be very hilly.

If you want comfort, I recommend a 23mm wide rim. That will allow you to use 25c's at a slightly lower PSI, a setup that will not incur any performance penalties. I happen to like the H Plus Son TB14's; there are lots of options out there.

I'd also pay close attention to your fit. You may want something a little aggressive in order to improve your speed, but I for one find that sitting a little more upright is more comfortable after ~5 hours on the bike. YMMV.