Ed-

Not a lot of help here, but a couple of thoughts.  When I'm clamping
irregular shapes I use surgical rubber tubing, most often something about
1/4" in diameter.  Start off with a few wraps in an open spiral, enough to
hold things roughly in position and then get the pieces lined up the way
you want them.  Then add more wraps until it is squoze to the degree
desired.  The more wraps you add the greater the pressure.  Squeeze out may
glue bits of the tubing to your project, but they are easily scraped off
and the worst aspect is the possible loss of the tubing for future
projects, but it isn't too dear.  Doesn't damage the project either, like a
metal clamp may.

This also seems like a project where another set of hands would be useful.
If you have some one with a bit of handiness that you could draft, it may
get things together before the glue sets.

Speaking of which, I'd pick a glue with a longer open time to allow for
fiddling.  But not too much ;-).

Phil