You can put in the equivalent of a sheer clamp, or bowed braes for the deck, or both, as needed. make these from short pieces of scrap wood and hold them in place with a few dabs of hotmelt glue. With these supports inside the boat as aids to align the deck, you can do things in reverse, that is, you can attach the outside of the deck first -- where it is easiest to apply the glass tape.

Once the outside is held in place with a layer of tape you can use a section of 2x4 and a hammer to knock loose those supports. A sharp blow and the hot glue should release easily, and the brace, or temporary sheer clamp will drop into the boat.

Just in case there might be any hotmelt glue left behind, try to apply it to the temporary bracing in spots that are not in the area of your eventual fillet and glass tape.

Once those temporary braces are out it is just a matter of putting in the fillet and the glass tape. The deck is going to be well secured by the exterior fiberglass taping during this, so you can flip the boat upside down, or align it on your sawhorses so the joint is on the bottom, and all the epoxy runs INTO it, instead of away from it.

Once the interior sets up you can go back to filling the weave, or applying a second layer of glass tape on the outside, and then sand and finish as usual.

Hope this helps

Paul G. Jacobson