For the rebuild of an old Motobecane (including sandblasting and a new powder coat) I decided to go with this Origin8 towntube shifter mount. I like the idea of the hinge rather than the traditional clamp that you have to bend to get around the downtube. It's a good idea and nice, sturdy construction. But after installation, the clamp causes the shifter/cables to stand off the down tube too far. The shifting is working OK, but it's odd-looking and cumbersome. So I think I'm going to take it off and go back to the traditional mount.
https://www.amazon.com/SHIFTER-MOUNT.../dp/B007Q4NKN2
Dan