I don't think you have to go to all of that trouble just to restrict the classes of ships they build. Just modify their DesignCreation file. Set the designs to hav size limits that exclude the classes that you don't want them to build. I'd really recommend that they be allowed small ships up to destroyer size even if you never saw these on the show. They have to be able to play the early game!
But then, you could cut off research on the standard ship design field and switch them to fighters/carriers. That would produce a pretty realistic imitation of the Cylons, I think.