My 2 cents...
I like to use the pace method.
link here
Anyone can go fast on the straights, the challenge is control in the turns.
When the leader hits a straight, he doesn't speed off, he maintains a pace, this gives following riders a chance to catch up if they need it.
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The other thing is this staggered formation BS......OK, it has a place when riding open interstates/parades/going through towns but once the riding gets technical...SINGLE FILE!!!
When you go single file you also expand your following distance (2 second interval is the very minimum).
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When riding with large groups, the "DROP OFF method" is my favorite technique.
There is a designated LEADER & CABOOSE. (often a flag or something is used to make those bikes distinguishable)
At any change of rt #, turn, or other potential confusion point, the leader "drops off" the rider immediately behind him. (with a pointing signal)
The DROP OFF then stays there and directs all following riders until the CABOOSE arrives.
Then the CABOOSE yields to allow the "DROP OFF" back into the pack.
The fun part of this method is for the faster riders because they can pass (only when safe & only on left & always properly signaling). They can work their way back up to the leader (but never pass the leader).
The slower riders can "ride there own ride" without fear of getting lost from the group.
Also this prevents congestion of the whole pack stopping and waiting at a turn (which can be dangerous or difficult).
Ideally the LEADER & CABOOSE can have helmet bluetooth (though there are times when cell phones or radios don't work)
In special circumstances, even if there are no turns for a long ways, a LEADER may get suspicious that there could be a problem back in the pack. He does a DROP OFF (who will be one of the faster riders) The DROP OFF waits for the CABOOSE & IF AN INORDINATE TIME GOES BY WITH NO SHOWS, he backtracks & either finds everyone coming safe or gets to the scene of a problem. He can then become a messenger back to the LEADER when communication devices are not working.