Each place has different sizes. The one I take mine to isn't picky on size but strongly prefer them not to be too thick so they dry easier after being washed. I cut my fabric into small pieces for the same reason and do NOT include thread waste. Remember the animals come in all different sizes so relax on the size.
Hint: one upholstry place sold me older style material for less than $1/yd once he found out what I wanted. I bought almost the whole roll. A real win-win-win.