I ordered mine from D & R and they were perfect. I believe I had to cut them to length, but don't really remember.
As far as reinforcing the chain plates. I took my bulkheads out one at a time, they were starting to show signs of water damage. They were still made of enough wood to pass my inspection, however I did seal the ends and both flats with several coats of penetrating epoxy. Especiallly the top edges and the existing holes where the chain plates bolted in. On the edges and holes I must have put a dozen or more coats, I kept it up until they would not absourb any more. Now at least if the chain plates do leak, a big problem on the 23 the wood will not absorb it and rot or delaminate. I needed to seal them about twice per season, so keep an eye on them.