I'm scheming my next batch, which will be my first mead. I was planning to do either 2 or 5 gallons. I've done a few batches of beer and one of Apfelwein, and the dramatic differences between US-05, EC-1118 and Red Star Montrachet krausen-wise have me wondering how much headspace I need. Can I do a 5 gallon mead in a 5 gallon carboy with Red Star Pasteur Champagne (I have some already) like I could with Montrachet, or will my foaming be more like Ec-1118/Ale yeast? What if I used something more normal for mead? How much headspace do I need?