Bruce & alasdair, wouldn't you want to reduce the total wing area figure used in the T.V.C. computation due to the inefficiencies of the triplane wings?

I naively/arbitrarily/experimentally/successfully used a figure of 85% on the last biplane I cobbled up and it flew great. Granted, it was small & light (250 sq. in/8 oz.) but the theory sounded right to me at the time and the resulting flying characteristics sure seemed to back up my possibly flawed thinking.