Both of my spinning rods for bank fishing are pretty short a 6' GLX and 6' 3" quantum smoke. I so much prefer shorter rods especially for bank fishing. It's so much easier to cast if you have to squeeze I between trees and such.
I see a lot of people recommending a longer rod for casting distance, my question is just how far do you really need to cast? I see you said you'll be casting 1/4 to 3/8 oz baits, in all honesty with a 6' rod you'll be able to cast those weights a country mile. Distance is not going to be a problem at all. I would go shorter then if your in a tight situation your casting is gonna be a lot easier.