If you can consider getting to the spa town of Bagni Di Lucca (Drive to Lucca and take SS12),we can recommend a lovely Italian lady that does not follow convention when it comes to teaching classes. Some of the ones above look too"Hollywood" or more to the point far too polished.
I do agree that the smaller the group the better. Mama Gabriella rarely has more than 3 people and if your going midweek you'll get this amazing experience to yourself
Last time we went was a few years back and thoroughly enjoyed it. Here's her email