Spent some time searching for 1" square forms Drew gave me. Gave up [Time warp 22MAY14: Found 'em]. Made new ones, cut to size and coated in packing tape.
Spent some time agonising how stiffener tapes will work through the leg holes with a 1" overlap described in the plans and only 0.2" foam to work with. Consulting the FAQ indicates Section B-B on drawing M-1 shows to just cut it off flush, and it does!