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That’s a good idea. I have used the high-value, long-lasting treat as a settling/attention-gaining technique and it works. I did have it come close to back-firing when a couple of pups started contagious resource guarding. There’s a fine line between a “valuable enough to settle for the reward” and “too valuable to give up,” especially with other dogs nearby.
I also like visual barriers to interrupt the process.

If (big word) the handler or I can get the dog’s attention, I like to use a high-speed drill/reward process, e.g. sit, down, stand, touch, sit, down, sit, down, etc., throwing out quick cues in random order with intermittent rewards to engage a barking dog and have them shift gears. The rapid-fire cues/random-interval rewards seem to engage the dog’s heads and stomachs pretty consistently.

The most challenging part IMO is getting the handlers to default to working their dogs when there’s a bark-off in class. Handlers tend to get embarrassed and then freeze up, so the barking increases and spreads. I like to stress to new students that all dogs bark, barking in class is to be expected to get handlers to be comfortable enough when it happens that they don’t stress out.

I am definitely looking forward to the alternate method technique.