The only reliable way to measure the fuel level in the bowl is to use a tube that attaches to the underside of the carb at the drain plug under the main jet. You can do it right on the car. You can even do it on a running engine, if you want to really see how it looks when running.
The fuel level in the bowl when you remove the float is subject to too many uncertainties, like fuel dribbling out of the float valve as you lower the bottom carb casting.
Measure down from the gasket seam between the 2 carb casting halves to the fuel level in the sight gauge tube. Many people will tell you to make it 5/8" down, but it is hard to tell exactly where the gas falls in that tube, and it is better to err on the "lower fuel level" side than higher.
So I aim to set the fuel at more like 11/16" below the seam, and even as low as 23/32". The engine will run just fine at those fuel levels and the uncertainty in the measurement means that the true fuel level is probably higher.
If you aim for 5/8" and end up with it a bit higher than that by accident, the fuel will potentially overflow the tips of the main jets and the carb will drip. That's why I aim for a lower fuel level, to make up for the measurement uncertainty. I don't like my carbs to drip.
