No, you're not crazy. My first, second and an assist on a third were 15", the first and the optics of the second are still in public use after 28 years. It is a lot more effort than a smaller one and the polishing, if done manually, would possibly kill the project. I built an Hindle machine to do the grinding and polishing and it still took many, many hours. I got a lot of satisfaction too.
Charles