The beer pours at 40°F, the keg line is 4 ft of 1/4"id hose, in the fridge entirely.
I force carb, and haven't ever looked at volumes of CO2 very accurately. I just rock the keg at 30 psi til it stops chirping (I chill the keg first) and then let it sit. I vent the excess pressure and then *try* to serve at 10 psi.
I'll check out that link right now and see what i can figure out.
As to the overcarbonation, I have had the gas low enough that it could essentially be off. I've had to deliver at pressures around 1 in order to not just blast beer/foam all over the place. Which now that I say it, makes me think that overcarbonation could be a very real issue.
Perhaps my problem is in carbonation, and not in the keg set-up.
rock and roll carbing is great. I do it all the time. but do it at serving pressure. yes 30PSI will get you there faster but it will also get you WAY over your target faster. set at 10, rock for 10 minutes or until it stops refilling. I like to hold my keg by the top handle and the bottom foot with the gas post down gas attached (never had suck back) and shift back and forth on my feet until the gas entry slows way down. It's usually okay after that but it's gunky and cloudy till the next day and the carb is better once it settles anyway.