You "balance" the carbs by getting the ideal color in the first
and last chambers. Once the color is correct the carbs are automatically
It seems to me that all this tells you is that the air:fuel ratio in the
first cylinder is fine, for the amount of air flowing through the carb
servicing that cylinder. And that the same holds true for the last cylinder.
I suppose if you adjust the throttle plate openings to get the correct mix
as well as the air:fuel mixture adjustment it may be possible to use a
Colortune to equalize the flow through multiple carbs.