I can provide you with my drawings if you want them. I sort of "came up" with them and don't know how they will work. It's great to hear from someone who sold tandems and has tried different ones. Builders don't seem to want to talk about their designs too much.

PM me your email address and ill send you a PDF if you like.

mine is still at the painters. I told him "no hurry". 'wrong thing to say to a painter (or frame builder).