Thanks - that's basically what I did. I got the measurement that way and then put the gunwales on the floor and put a board where the backrest is marked. put a board where my feet ended up when I sat in it with my back at the backrest. That's where it's going.

Moving right along, I had trouble getting the curves to cut out of teh tops of the gunwales but stole/borrowed a strip out of my wife's current Gullimot project and pegged it with some manually-hammered brads from her air nailer thing.

Jackpot. Currently working on smoothing out the mess I made removing the material with a hand plane of some description.

Tomorrow after work it will be in the forms and the fun-looking task of kerfing the ends will start. Not how many beers THAT task will be...

:)