I ordered them through a model ship plans company in the mid 1980s. It may have been Taubman Plans Service, not sure. Franco's plans are magnificent, and very easy to follow. He drafted several plans and marketed them, at least six or seven as I recall.
Now I use a book called The Encyclopedia of Battleships, and Jane's, to scout out new modeling prospects (predreadnought ships). The colored drawings are magnificent. Like being in a candy store. Then I go online like everybody else, find plans of what I want, blow them up and try to make sense of it.
With Potemkin I blew up Gay's plans to make 1:160. His were 1:200. So now I am making all my predreadnoughts at 1:160 for comparison purposes.