Jim, you mentioned staying 20 cm. from a curb. The rule is 30 cm. (1 foot) from a curb. The 20 cm. is the distance from a painted line on a track.
I still have a letter from Ted Corbitt which starts out, "The old one-meter rule is dead." He goes on to say the rule is now 30 cm. Anyone else still around from the days of one-meter?