I mostly brew small batches -- 2 gallons or less. I've done ok using a full pack of dry yeast, but I'm wondering what would happen if I just used a full pack of, say, Imperial. They quote 200B cells per pack -- that'd be like a 4x over pitch according to Brewer's Friend.
If bad things would happen, what would be the best way save half a pouch of yeast between brew days?