Dan,
Here are a couple things I noticed when building the Sea Duck from the v1.0 plans.
The first is on the hatch support (part #8). There is an area that should have the foam removed.
The second is on the fuselage (part #1). There are two areas that should have the foam removed. I wasn't sure when I took the screenshot, so I just put the "?". I went and watched the build video to verify.
Also, that the little piece on the bottom trailing edge of the fuselage (on the right edge of above image) is actually an A fold, not a B fold as the plans show.
Bixler shows an A fold in the build video here.
I made it an A fold and everything worked out.
Thanks for the feedback dayve, I will incorporate the changes into the next revision and get those out ASAP.