No they need to be set for the best running, per engine demand // usually they pretty close side for side, but not always. If the engine is happy with where those adjustment screws are positioned that's the important thing
I don't remember any manual saying they have to be equal in number of turns out, when everything is set for the best running.
Set the same as a starting point upon a rebuild or just plopping a certain carb on a particular engine? Yeah. But if one side is 1/2 a turn different from the other and that's what the engine wants? Who cares
If you're just doing a tuneup and going over the adjustments when you get to the carb you're probably not gonna bottom them out and start over .. just gonna tweak it from where it sits.
So, often you won't actually know how many one mixture screw is from all the way in vs the other one
