There was an excellent surf guitar article, by John Blair, in the September 1996 issue of Guitar Player Magazine. He interviewed five top performers and one of his questions had to do with string gauges. They all agreed that heavier strings were necessary to get that sound. Here is a list of the performers and the gauges they were using at the time the article was written:
Dick Dale: .016, .018, .020, .038, .048 and .058 / .060
Don Wilson (The Ventures): .011 - .050
Danny Amis (Los Straitjackets): .011 to .048
Mikko Lankinen (Laika & the Cosmonauts): .012 to .052
Jim Thomas (The Mermen) didn't specify the gauges, but did say that he uses heavy strings.