I was wondering if any of the Akafliegs had
studied this but couldn't find anything on a Google search. I did see
one study by NASA on a 747 towplane - towing a proposed freighter
glider but you had to order it, so i didn't read it.

Apologies for the above, I found some pretty relavent links by searching
on Formation Flight Aerodyamics, so I'm sure it's all been worked out.
But maybe not as well analysed yet for the particular problem of a heavy
glider on tow.