Sorry to hijack your thread, but I have to know -- are these 5-gallon Cornies? Is blowoff a problem? Do you use Fermcap-S or just settle for less beer?
I ferment in cornies as well; they have a lot of advantages over carboys. Usually I use 10 gallon cornies, but I've also fermented in the 5 gallon ones. I've fermented up to 4.5 gallons in a 5 gallon cornie without issue and without using fermcap.
It's great being able to transfer to the serving keg under CO2 pressure without even having to open your fermenter.
Just stick a piece of tubing onto a gas disconnect, and you're good to go.