I've torn my pieces into 13.5 x 15 for the most part. You get the same amount of square inches of would allow you to use my piece as a full 12.5 x 12.5 background if you wished to applique on it.
Be glad to get all the info .... Dad ironed and wrapped all the pieces today so they'll fit in the envelopes so I just need to do my labels and notes.