Late to the discussion about tee time intervals, but I think the best way to figure it is to determine which hole on the course takes the longest to play, and set your interval based on it. The idea being that if the interval is maintained between each group, the closest you get to a bottleneck back-up is on that longest hole (which probably is still long enough that a group can tee off safely while the group in front is still on the hole/green). No big back-ups for anyone all day trumps all, IMO. So if you've got a par-4 or par-5 that the average 4-some is going to take 15 minutes to play, 15 minutes is the right interval.
Of course, if you've got a big field where such an interval means you've got people teeing off too late in the day, you can adjust it so that each group can complete the round without rushing to beat sunset. But otherwise, why not use as large an interval as you can get away with? In some of tee time events I've played, the scheduled interval was too short for groups to even complete hole one. The result was that everything got backed up right away, and the longer or tougher holes later in the course were bottlenecked by the time the third or fourth group reached them, and stayed that way all day, which is no fun.
Maine Disc Golf
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