In searching the web I found the following quote from a book on the history of Mexico:

"At the Casino de la Selva in Cuernavaca and the Foreign Clubs of Mexico City and Tijuana, which he owned, the well-off played roulette, drank highballs, and had a good time."

The "he" referred to in the above is Abelardo Rodriguez who later became President of Mexico. The book title is:

Triumphs and Tragedy: A History of the Mexican People
By Ruiz, Ramón Eduardo

So perhaps there were 20 tables - just split between Tijuana and Mexico City??