Shorter the boat, shorter the rod.
In a 12-16' boat, you are unable to back away from the gunwale in order to hold the fish within reach for netting, use a shorter rod.
Bigger boat, 8' beam, you can take a step back to bring the fish alongside, longer rod ok.
Fishing alone, I prefer the shorter 9' rod as I can be at the gunwale and net the fish easier than with a longer rod.
Shorter rod, easier to control the fishes head when landing.
9' is, in my opinion, the more versatile rod length and about all I use.
In the old days when we actually mooched live herring, Hardy 10' and 10'10" (fibreglass) were the cadillacs. For mooching, as gungadin said, you wanted a very soft tip. Soft enough that you could see the tip straighten when a fish took the bait and picked up the weight of the sinker - usually we used 2-3 ounces, occassionally up to 4 or 5 if the current was pushing.
With graphite rods you can get a soft tip in a shorter rod if you prefer.
Let us know how you make out with a single action reel, Bill. Took a look on the net and couldn't see a mooching-single action Quantum reel.