Does anyone know of a source of technical information regarding the
Recordo and Ampico Model B expression systems?  Specifically :-

What is the official rewind duct for Recordo?  The rolls I have all
seem to allow for every known standard (and some unknown ones !)

What are the differences in the expression systems of the Ampico
Model A (which I know & love) and Model B (which I've never seen) ?

Thanks

Richard Stibbons MIMIT
Cromer, Norfolk, England