Step 1: Scan the sample, trace its outline
I exported the extrusion in the STL format, and loaded it into Vectric's Cut3 tool-path software, and created a cut file. I selected an 1/8", ball end router bit to do the cutting.
Step 2: Make a jig to hold the wood firmly
Step 3: Cut it!
I ran two tests - one cutting along the long axis of the wood, and the second "up and over" the short dimension. I was surprised to see the second one gave much better results.