If I haven't done the math correctly, please weigh in.
The contest web page is a bit short on specifics: http://www.contest2018.nz/
Their Facebook page: https://www.facebook.com/contest2018/
Bands are in classes A, B, C, D, and youth. Bands must march a parade Friday at 1pm; youth division seems to be exempt, but there is only one youth band according to the postings. On Friday, bands in A-C do a sacred selection and a contest piece, and on Saturday, all bands play their choice selection. BrassBanned will run two streams, one from each of the contest locations.
The first group plays at 8:30am Friday, which my calculations say is 4:30pm Thursday EDT in the US.
Handsome Tim (Tim Kelly), the operator of BrassBanned.com, usually puts up a schedule of groups a day or so before the contests begin. Please note that there are 10 A bands not counting no-shows and that they begin at 4:30 pm each day, so this level could run on 6 hours or more. That makes them very late at night in the US (or early in the morning, if you prefer).
Tim is an Australian brass bandsman who proudly plays a Conn 25J and displays it prominently on BrassBanned.com.

