KK, I’m not sure I understand. I mean being close enough as a timer on a three turn stagger to find the middle of the exchange zone for each lane so the legs are of equal length and not 395, 405 etc. Most of the tracks I’ve seen have either a solid or dashed line in the middle of the zone (for each lane) and it’s usually well up into the curve from the middle lanes on. I think only lane one has the same line (which is the finish line) for all three exchanges.
By timing the baton I mean when it crosses first the middle of the zone (for each lane, not the common zone so it tends to be further into the curve for most of the lanes) for the first exchange then timing the baton as it crosses the finish line for exchanges 2 and 3.