That sounds good but won't the 1 target standing in 1 minute lane mean it is cleared for the next group more quickly? With a queue forming on the subsequent lanes? Maybe go the unthinkable - 3 standers, 3 mins and the next lanes will be eased?
Some spend quite a lot of time pulling strings, tossing leaves, dust, powder getting settled which is all good but maybe that needs an experiment added to Rob's list. Maybe 30secs after sitting down before the eye-to-the-scope clock starts or something else along those lines? I always pull the strings just to make sure I know which targets are which especially since the numbers can be hard to read (e.g. at the Inters where a black number with a silver border on a red plate - looks pretty but they all look the same until you put the scope on them). And as for crossed strings. Alternating colour plates between lanes would reduce the need to check?