@Stan Galat, to some extent it was just something I did but after a lot of research, including reading most of the Samba thread.
I did not perform an in-transmission comparison of several trans. lubes as you did.
The price of the 201 varies from place to place. It is worthwhile doing a Google search.
I have an extra jug I ordered when I had the trans. side seals replaced. I thought more would leak out during that procedure.
The builder of my trans. suggested Lucas but I don't see other recommendations for that.
I let a guy drive my car who owns several Porsches, from 356 to 911. He operates a large repair operation with a Porsche only section called Rennstatt Racing. He commented on how great the shifting was with my Vintage Speed shifter and the 201. Maybe my brass shifter bushing helped too.