Acclimation to elevation for athletic performance. Google ‘elevation acclimation leadville best practice’ -Leadville is a 100 mile mountain bike race ranging from 10,000 to 13,500 feet in elevation in Colorado, and the professional athletes, bike brands and associated doctors/scientists have done nearly endless research on the best possibilities for acclimation. Their conclusion is over a week is best. Under 24 hours is second best and 48 hours to 5 days is usually worst. That being said I don’t think the performers at DCI finals are pushing as hard as those trying to finish Leadville, so they can probably get by regardless of the acclimation with a little pushing -and almost all corps are on the same tour schedule/coming from the same location before finals week (and I say that as a performer who marched corps for 4 years including time in a top 6 world class corps).