Hi Ben.
This to me is the best compromise for this type of coupling and would be of interest to me in both long and short versions. The short version especially as the Farish version has too small a diameter of side pin, which means that they do no lock into the box. I have had to use their long version so that the coupling doesn't pull out under very little load. A very good idea that I hope comes to fruition.
Regards
Howard Staniforth.