Hello Craig, welcome to the exciting world of biodiesel
Unfortunatly the biodiesel production information on the JTF site including Mike Pelly's method is out of date and contains inaccurate information.
Adding vinegar (acid) to the wash controls emulsions by turning soap back into FFA's. This is not desireable.
For the latest thoughts about home biodiesel production I suggest you visit the
Collaborative Biodiesel Tutorial
Tilly