My third and fourth guitars were built as “twins”, with all the same trim details, but one as a six string and the other as a twelve string. I chose to build them simultaneously to see how the “economies of scale” came into play on jig setups, etc. For the most part this worked on all machined parts and bending, but fell apart when it came time for hand work. At that point, everything just took twice as long. Still, I got it down to 60 hours per guitar. Not bad considering 25 of those hours were lacquering. Materials used were: Tonewoods, Curly Koa: Bindings, Curly Maple: Purfling, Paua Abalone: Fingerboard and Bridge, Indian Rosewood: Nut and Saddle, Black Horn