In principle Scott is correct -- attach the forward deck to the fuselage,
bond a frame onto it, remove the deck, glue in the header tank, put it back on
the fuselage.

In practice, there will be some minor warping of the forward deck during this
process.

The warping in my case was not so much that it has been problematic (my
forward deck is screwed to fuselage), and in fact there has been some minor
relaxation over the years since this was done.  It no longer takes a lot of effort to
get all the screw holes to line up, though it did at first.  However, I'm a
little nervous about getting a hinge pin to drive thru a long hinge with the
warping that I had.

- Rob Wolf
(drooling over Dan Olsen's airplane...and looking forward to a ride...)