First timer here. Starting small, using a Mr. Beer for primary fermentation. Then, can I use a 3-gallon Better Bottle Carboy for secondary fermentation? or is the half gallon gap too much? i.e. does the carboy have to be mostly full? to what extent? And should I also get another 3-gallon with a port so I can transfer to it before adding the corn sugar? Seems like if I second ferment in the same carboy I'm to bottle out of that adding the priming sugar will disturb the sediment defeating the whole purpose of secondary fermentation. Thanks!