I ran into this same delimma a couple days ago. I have a stick lf purple/grey and a stick of yellow/grey currently drying to each other. I am then going to slice the two sides off of them, and pair those two sides for another stick. When I put the barrel and the stopper together, I plan to twist them to be opposite of each other. This is not too exciting, but its what I have decided to try when the guy was sure he wanted spectraply and not real wood. I could just have a stopper purple/grey and a barrel yellow/grey, but that's NO fun.