As I said earlier I have tried them and in my opinion they work. It is out of pure choice I went with the relax a lock, as they looked the easiest to make at the time and I wanted to copy them. I used washers for a while as a stop gap which I believe can work quite well, but never continued as I thought they looked ameater.
I haven't yet found a good way of copying the relax a lock with my limited toolbox!