Yes, I used them on a set of Mafac Racer Brakes. they're a pretty big PITA and required a lot of swearing on my part but the end result is worth it IMHO...I think they look great.

First you want to start with the straddle wire only connected to one of the canti calipers. The trick I found (in the absence of any instructions) was to remove the pulley, install the hanger on the brake cable, then reinstall the pulley and straddle wire together. Finally Hook up the other canti caliper and hope that you adjusted the hanger in the correct position. Curse, then repeat until you get the hanger adjusted at the right height. Maybe its easier on canti's than Centerpulls.