I'd say a couple other things: even in summer, I sometimes go out for 2 hour training rides and don't drink anything. In winter, say 55° and on down, I may drink as little as 12 oz. in three hours of hard riding. My performance is not decreased by slight dehydration like this, in fact it is probably increased. I also don't cramp.

Cramps on the bike are invariably caused by undertraining, hard as this may be to hear. Night cramps are another story. No one knows why those occur. Cramps, whenever they occur, including incipient cramps that haven't fully developed, can be stopped in seconds by eating 1-2 regular, name-brand Tums. This works for everyone who's tried it AFAIK.

As far as researchers can determine, cramps have nothing to do with hydration or electrolyte levels, either on the bike or at night. Good study of cramping in athletes here:
http://www.sportsscientists.com/2007...ramps-part-ii/

I probably should note that I've done a bit of riding, including double centuries, RAMROD, and brevets, up to 18 hours of riding/day.