For such short "strips", it's conceivable that he didn't use cross sectional forms perpendicular to a strongback (classic strip building style) at all. Perhaps he used a full surface form, like a balloon or a foam model, like making a paper machie globe for the science fair...
As an experienced canoe builder, I would think that the square edged wedge shaped "strips" would be very easy to scarf together. Even if they didn't make strips with flat edges, they could still puzzle piece together if they were scarfed together in a regular pattern, making a strip to strip seam like a masonry running bond.
In fact, I imagine the "strips" would be more than one chopstick wide. When complete each one would look like a long piece of wooden low-angle
rickrack.