If youre talking about in the bowls, for sure matters. Can't say that a .1 change is enough to notice anywhere except the dyno though. I've gone from top of the sight glass, to below the bottom,.5 and saw enough change to effect mph. With all the sloshing, g forces, and float bounce that goes on in a normal carb don't think it's a way to tune.

I have a few sets of bowls wj used when ps was on carbs. The floats have hydro shock absorbers and tons of work in them to control the fuel level through the run, and they just stuck with one position for the floats.