: As far as thwarts vs. frames go, I guess the choice is between
: interference at the gunwales or on the floor.

I'm not sure that is your real list of options. You'll find it faster to define the boat's shape by making frames and bending boards around them. At least one frame.

You have the option of bending chines around the frames and attaching relatively thin plywood to the chines, or, bending thicker plywood or boards around the frames.

The question then will be whether to leave the frame in the boat.

Instead of thwarts you can install simple plank seats.

Google ' uncle John pirogue'. Besides selling plans and frame kits there is a link to a redacted set of building instructions on uncle John's site. The measurements are removed (but fairly easy to figure out) and you get a good sumary opf his building process---which is pretty simple.

PGJ