I've been looking for something like this also. What type of rope are you using and how long have you had the cleats? How did you mount them, they look too long to have both end screws in the canoe spreader bar.

I'm also wondering about rope wear, I've been using a standard cleat and, because its metal and starting to rust slightly, it's starting to fray the poly prop rope I've been using. I was thinking of using the quarter round cam cleats but haven't been able to find them or any one that is using them.