The set of plans that I built my T from were purchased direct from ITA. From memory, I believe one set of plans entitles the purchaser to build 5 boats, although royalties need to be paid on each boat built.

Our boat was built in a similar way to the Gougeon boat shown, with lots of thin bracing and trusswork. The plans don't show this but it is relatively easy to work out for yourself (to replace the re-inforcing shown).

Our main problem was getting access to the official IYRU (ISAF) measurement templates so that we could check shapes as we progressed. Fortunately a friend knew someone who had a set that they had made up themselves in ply rather than the aluminium of the official templates and they were good enough!

If I were 30 years younger, I'd do it all again