Well to report back I didn't even try really - the bushmoot was just too good I was only at my tent to sleep and 10mins to cook each night!

I suspended it over the hammock so I had enough room to comfortably sit in my chair, almost stand up etc. But the general answer is no, you couldn't do it diagonally with the prusiks because the tarp is too long. For a straight over fold, that's almost exactly what I did and yes you could do it that way. but there's not a lot of space let over but the DD tarp does have suitable holds for them but you might need a little paracord to join them.

Hope that helps!

There's a pic on flickr btw - just look for tim_neo/bushmoot 2010.