Your other option is to stick with the original friction
shifters. Cleaned up and ajusted properly, they do shift
nicely, though it takes a little time to learn how to make
perfect shifts.

I'm a fan of downtube friction shift and run it on my daily commuter, but the centurion project is supposed to end up with a set of Campy Veloce Ergo 9 speed shifters. Rebuildable, for the last bike project and usable for fast riding, touring, and light cyclocross riding. Currently I have a standard set of adaptors and a file. I think it'll work, but it may take a couple of tries, and even the screws on those downtube mounts are a non-standard size.