Over the years I have used the single ‘long’ type C-clip on 4 different V-8 engines, and the 2 'individual clips' type on another one - all without any problems. A statistically small sampling for sure, but I don't know of anyone that has reported one coming loose; at least if they’re installed properly.

Off topic: It seems strange to me that all the 617 diesel chains are crimp type only; with such short chains, it seems like they would be a good candidate for the clips…

RTH