Interesting. Most free sailing models, especially on the West Coast of the USA, were trimmed to carry substantial lee helm. For a Braine gear boat, this was done to prevent the boat from heading up and going into irons on a gust; it was better overall to sail lower. For a vane boat, lee helm meant that the wind pressure held the self-tacking vane "broken back." The big advantage of the vane was that it enabled the boat to point higher. For those who want more information on self-steering models, see:
http://www.usvmyg.org/freesailing.html
Cheers,
Earl