These once cooked freeze well.
There are many ways to measure how much mix goes into the pan, measuring cups, ice cream scoops etc, I like to live dangerously and I just use a tablespoon, usually the one I made the mix with.
This is so much better for you than the pre mixes and its made with what you have at home already.
Don't want to use vinegar, try using a table spoon of fresh squeezed orange juice instead, similar acidic reactions.
Out of this mix I generally get 4 pancake sized for dessert and 6 pikelet sized to be buttered and jammed up for the next days lunches.