Originally Posted by
OhNoCB
About an hour or so. Also remember to switch fuel tanks.
Not a particularly unique system, but I just use the long hand of my watch.
If it's pointed right, I should be on the right wing tank; if it's pointed left, I should be on the left wing tank.
Tends to ensure a tank change about every half an hour, keeps me in balance, and requires virtually no mental effort to get right.
G