: I am able to use a local lumber supplier in Montana, and as a cedar
: specialist, they have started stocking 18' - 20' lengths of clear cedar
: for boat builders. . .

Please mention the name and address of such a supplier. Others will want to get materials from them., too.

If you want to add a small amount of strength to your hull you might try to take advantage of the grooves created by the over beveling. Fill them with linear glass strands. It is a messy and time consuming process, so nobody does it, but it is something to at least discuss.

For years boat builders have left slightly beveled gaps between hull planks, and then forced in a fibrous material to fill or 'caulk' the joints. The caulking material, and the wood absorbed water and would swell, sealing the many long seams between boat planks. Those bevels were on the outside of the boat, and yours are on the inside, but the idea is similar. In your case the linear strands of glass fiber would have considerable strength.

You would use a hypodermic syringe to apply a tiny amount of epoxy in the grooves. Perhaps it would be neater to just put in a drop or two every inch to stick things down. Then you would lay in strands of glass fibers to fill the grooves. When the epoxy hardened you would have each cedar strip connected to its neighbor by a triangular strip of fiberglass-reinforced-epoxy.

Making the linear fibers is easy.
If you have some scraps of glass cloth, cut strips 1/4 inch wide and any length. A gentle tug pulls these thin strips apart, giving you lots of 1/4 inch fibers for thickening or reinforcing resin later--and you also get long bundles of glass fibers for 'caulking' these seam grooves. depending on your patience and skill you could conceivably lay in continous strands the length of the hull, but I think that it would be easier to work with pieces which were about 6 inches long.

Just a thought.

PGJ