It will vary startlingly during the day. I've got runs logging anywhere from 5800 to 7200 feet.
Better to know before the run, wouldn't you say?
If you're able to make quick adjustments in line, post a team member over by the timing shack and just ask what the DA is. We changed out jets on the Weber 3 times in one day in 2013.
If you're running EFI, for most systems, it's automatic, and not a big concern.
But it's a very useful tool with carbs, if you're looking for that last 1/10th.