I fitted the Zefal Shields last night to my son’s TCX1 (which has canti’s and no brake drillings front or back).
Overall I am quite pleased with them, they were more of a fiddle to fit than the raceblades but seem relatively sound once mounted. They have metal stays and attach to the frame with either the supplied rubber mounting bands (quite substantial) or cable ties.
I had to do some cable tie wizardry to attach them to the rear bridge and needed to drill a couple of holes in the front one to enable me to cable tie across the top of the fork bridge.
My only niggle is that there is a small amount of side-to-side movement on the stays (seems to be by design). Apart from that they seem like a viable alternative to raceblades and crudcatchers.