In your "convinced that the Kraeusen needs to be skimmed or blown of", I assume the "blown off" part refers to us carboy types. How much headspace do you think it best to start with to get the correct amount of krausen blown off without blowing off too much other stuff (if that's possible)? Since I usually do 5.5 gallons into the primary and I just got a six gallon Better Bottle, I think I'm probably good to go.