The timing on zigzags is indeed squishy. That means the choreography can fit it one way or another, but dancers will be prone to get there early or late if it doesn't fit well.

Here's something to compare with: allemandes. I think it's well-established that allemande 1+1/2 takes 8 counts.

How about allemande half? Is it 2 or 4 counts? Depends on the choreography.

Allemande once? 4? 6? Those are common, but even 8 is possible.

Allemande twice? etc.

Context matters here, especially when the figures before and after may also be squishy. An allemande gets less time if it's preceded by, say, a circle left all the way, vs. a circle left 3/4.

Also, when we say "allemande 1+1/2", sometimes it's really 1+1/4 or 1+3/4. Similarly, what comes after the zigzagging affects its distance - zig left, zag right, new neighbor allemande left doesn't require you to travel as far as zig left, zag right, new gents allemande left (which is almost, but not quite, zigzag past 1+1/2 couples!).

All that said, I agree with Tom, but my opinion is that zigzag past two couples fits well in 8 counts, and zigzag past one couple can fit in 4 or a little more, like an allemande once. It depends.

Yoyo Zhou