Stephen Harker wrote:

It would be interesting to have some real information on this. I
would expect that, to a large extent, when flying in formation the
pilots could compensate by the throttle setting, after all when on
patrol they would be flying at considerably less than the maximum
speed and hence it was less of a problem.

I haven't been following this thread too closely but if it hasn't been
mentioned yet, remember that those old WW1 rotary engines didn't
have throttles. The pilot used an "interupter" switch to alternately
kill the ignition and restart it so as to adjust their speeds. A good
example of this technique (called "blipping") being used is in the
1975 movie, "The Great Waldo Pepper" starring Robert Redford.