Thanks for the good tips guys, I guess the camleback straws must be more flexible than they look, couldn't have imagined being able to get one up inside my helmet!
I used to go to SA fairly regularly (family was all over there) and found that the two hour break rule suited my concentration and comfort levels just fine, car or bike, but six years ago I started working for a company which sends me all over the state, so I spend a lot of hours on the road, usually on a fairly strict schedule. I found that my driving 'endurance' increased a lot, I feel as though making 4hr stops is reasonable now... But I do wonder, how much of that is true endurance from 'conditioning', and how much is my brain just being accustomed to working when it's totally knackered... ie, is the 2hr rule still the go, even if you're feeling fine? This time of year when I'm not working & traveling as much, my endurance definitely diminishes!