How much does 1 jet size affect A/F?

^ To add to this further here's a copy of what I posted on a similar thread awhile back:

You also might want to try this trick out of the q-jet tuning manual By Lars Grimsrud:

When set up with the correct metering rod for cruise & idle, will produce a slight hesitation upon acceleration if the
accelerator pump is disconnected. I do this with the engine running so I don’t have any trouble starting the engine without the
accelerator pump. With the pump disconnected and with the engine running in neutral, “flick” the throttle just a little. If the engine
actually feels more responsive with the pump disconnected, your cruise metering area is too rich, and you need to install a fatter set of
rods. If you get a severe stumble, or if the engine dies, you’re on the lean side and need smaller rods. When the rods are correct for
the jets in use, you will get a slight hesitation when the pump is disconnected.


After your done verifying the jets and rods are good, watch this:

[ame="https://www.youtube.com/watch?v=Kw-8lv4QIfQ"]Edelbrock Carburetors - Troubleshooting - Hesitation and Stumbling - YouTube[/ame]


Once you have set the rod size up like this, using the disconnected accelerator pump, a road test is in order. If the car is a little “flat” on light acceleration, or if it has a slight “surge” at steady cruise, you need to richen up the metering area slightly. If it is smooth and responsive on light acceleration, and feels smooth at cruise, you have the rod size nailed down.

Again, use the charts to keep all changes limited to 10% at a time. This will prevent you from “over-shooting.” Remember, with the
main jet size determined, your rod sizing is affecting idle, off-idle, light acceleration, and cruise. In most cases, when there are
problems with stumbles, poor idle, idle speed that starts out high and then degrades, and surging at cruise, the rods are too big and are
causing a lean condition. On the other hand, if the rods are too small, causing a rich condition, the throttle will feel “lazy” or “slow”
when you rev the engine, and you may get a puff of black smoke with a hesitation when you “flick” the throttle. Correct rods will
produce crisp, clean and instant throttle response.