FCS plug?

Hi... how thick are FCS plugs? its my first time glassing a board and installing fins and havent a clue about this stuff. im worried my tail is too thin to take a plug. what would be the minimum thickness in the tail for a plug?

thanks

lots of stuff about this is in the archives and fcs has a 50 page pdf guide on how to install their plugs. its definitely a valuable resource and you might even be able to put a cover on it and put it on your coffee table if you are a big enough surf nerd ;)... 1 inch is minimum if i remember correctly.