I guess Holley doesn't know anything about carbs either, since they recommend a 570 CFM carb for that combination, using their online carb selector.
Also, you might want to look at
The other thing you are wrong about is that too big of a carb does NOT go rich when it gets to its flow range, unless the power circuit activates. A carburetor is a dumb piece of metal, and doesn't know how fast the engine it is mounted to is spinning. It is calibrated to meter a specific amount of fuel to a specific amount of air. The reason a big carb does not work on a small low RPM engine is because it takes a higher air flow to start the fuel flowing through the main jets. This is because the bigger throttle bore and venturi do not create as much of a pressure drop as a small throttle bore and venturi. Imagine putting a very small hole in the side of a straw, and sucking through the straw, then do the same thing with a piece of garden hose. The air speed through the garden hose is much slower, and it does not create as much of a suction through the small hole. This is not the "exact" way a venturi works, but it is similar.
What usually happens on a carb that is too big for an engine is that when the throttle is pressed, the accelerator pump dumps too much fuel, and eventually that fuel passes through the engine. What happens then it the engine goes lean because it is getting all the air it needs, but the airflow is not creating enough of a pressure drop across the venturi to start the main circuits flowing.
Holley vacuum secondary carbs are quite forgiving as far as sizing, and you can over carburate somewhat without any problems. I'm not saying you can hang a 900 CFM vacuum carb on a 304 or 318 that is relatively stock and have it work, but a 600 is definitely doable.
By the way, you should probably invest $16 in this book