Believe me, unless you have STRONG reason to and are a tuning guru, you do not want to change any AIR jet on a carb. Not as simple as fuel changes, and much harder to understand the effect. Changing a fuel jet pretty much richens everywhere, change an airjet or emulsion tube and you change the entire CURVE of fuel, say low fuel at low rpm to high fuel at same rpm but the same fuel amount further up the range. The change is NOT equilateral across the whole spectrum of the jet use at all. Think of a steep ramp as versus a shallower one, but with same fuel at the top, or same fuel at the bottom. Now take that steep ramp and grab it in the middle and yank it one way or the other, what airjets and emulsion tubes can do. You can get lost there so fast it's not funny.
When you have a carb pretty much dialed in like stock ones are you are dollars to donuts miles ahead by changing fuel jets only.
Say I have car that runs too lean at less rpm and too rich at higher, all at WOT so mainjet only, how would you correct it? Think about it. Oh, and I took the power valve away from you too........... .............. .....