Hi David,
Yep reached the same conclusion as yourself. I had measured incorrectly and now have set up with 12in from #15 aft to #9 and 12" from #2 to #8. The distance between the fwd side of #9 and the aft side of #8 is 11 inches using 0.5 inch forms. Unless I'm told different I can't see any other way they will fit?!.
What do you know about sheer strips then
Podge

Hi Podge
: I ran into the same problem and it sounds like I'm at the same stage as you
: are in the building process. I have measured this @$@$#@ thing at least a
: dozen times and no matter what I still end up with the same problem. Even
: if I could fiqure out what was wrong my strong back has already been cut
: to length and I think I would run out of room at one end or the other if I
: try to make the full 12" adjustment for all the forms. I'm not very
: experienced at this because this is my first kayak but my logic was that
: the small adjustment that would be required to center form #8 should not
: make that much difference in the overall kayak. Of course I'm waiting for
: a deluge of responses telling us that this is not so.

: Dave