There's a tradeoff between speed of lookup and ability to find things when you only partially recall the name. For those situations (the "tip-of-the-tongue" phenomenon), I'd pick either the first and final letters as the easiest to recall, or the first and second letters. The fourth letter won't be easy to retrieve unless you recall the name exactly.
The reason I used English corpus words was precisely that I did not have this surname frequency list handy.
I don't think this is a list of English names, though. #18 is Garcia, and #19 is Martinez, and so on. It's a list of US names. A similar list for Argentina would probably be most useful for me at the moment.
https://gist.github.com/bd9fabf91a5501b215c5
(I copied the names table from your link and applied the original program to it)