Yes it is a little tedious and adds more steps, but when you end up with a perfectly fitting plank, it's worth every minute of tedium.
As luck would have it my 14 year old son joined me today, as he is off school on mid term break this week. Together we turned out the perfect plank and he's probably wondering what all the fuss is about!
Simply pinned the battens to the desired upper and lower edges of the planks and hot glued the trellis between the battens to hold them in shape. I then nailed the batten to the planking stock, removed the trellis and then continued as before with the circular saw jig and router method which John Brooks describes in his book - GLWB.
I also sanded back some the the planks at the transom to see how the dory gains were had turned out:-
You can see where the cuts on the underside of the plank allowed it to bend onto the curve of the transom, but at the same time the third plank has not completely settled down onto the transom, the lighter shade shows the epoxy glue filling the void - not that it will be any less strong I imagine, but it's still a fiddle to get both boards mated and sitting snug into the curve of the transom.