Research the math! Learn about the process and machine tolerances so that you do not have to take a salesmans word for it. Rather than calling the phone bank over at summit try calling the tech line of the cam manufacturer for example. If you want to learn about a specific area or product talk to the ones who do it every day, and then talk to another one. Get a few opinions and points of view. Then it is time to take what you have learned and think for yourself.
Tech articles in magazines are rather product specific. Try your local bookstore/library. Look for books on engine performance math and theory. I know it sounds scary, but most of these books do a fairly decent job at explaining the basics. Your basic parameters of the engine will depend on how you intend to put the 454 to use. The suburban is going to be a worker so you dont want to get crazy with the motor. You most likely wont be looking for power at high RPM, mostly off idle to 3000 maybe 3500. I assume that you intend to use mid-grade gasoline or higher, so you will be generally limited on your compression ratio to about 9.5 maybe 10 or so. The power band and compression ratio are good general ideas to consider when looking at a cam and fuel delivery system. The RPM use will determine the size of the carb, too big of a bore will slow down the velocity and not live up to the potential of the cam/head. Too small will suffer on the top end where it will not keep up with the airflow requirements. Personally I would favor the smaller bores for bottom end if you are looking at a working class motor, but definitely speak with the manufacturers with some hard info on your intentions.