This is something of a stealth update, as I have no actual progress to discuss, or even photos to share.
However, I've been speaking with a freelance welder recently, working on getting a quote for the caprice stretch. As mentioned previously, this is a critical component to the build, and one I'm not willing to risk to my own meager talents. So I'm hiring a big gun. The price is not cheap, but I figure it will be money well spent.
We've both agreed that the right thing to do is to wait for the shell to show up so we can get measurements directly off it, to make sure it fits perfectly.