Looks much more fun for the kids than a seat behind you- certainly much more sociable! (One of the reasons I built my quad- it was really hard to talk to Mrs IRW on the tandem). I was a little alarmed when you mentioned that you just need to undo some wingnuts to separate it though...I appreciate it would involve carrying a ratchet spanner or socket, but would nylock nuts not be a little less inclined to loosen themselves on such a critical point?
Ian