Reading Spark Plugs

I'm bringing the 600s, new plugs, and cam specs to a competent friend/mechanic on Wednesday. I'll share this thread with him.

What is the difference between the 390 and 600 carb?
Is it that on a 600 you can change air bleeds, idle feed restricters and emulsion, 390 you cannot, or is there more to it? Not that I've ever done any of that myself, but I can learn.