Light mount, swivel adapter needed

Imagine if you will, a boom arm used so a studio light can hang from a spigot. This spigot would obviously be pointing directly downwards.

The flash (Bowens 500) hangs happily on the spigot and all is well until I want to turn the light left or right.

For good safety, the light should be fully tightened, but because the lock screw has a spring it can also be loosened off slightly and still stay in place.

However, this ends up carving away at the spigot (which is a steel "drop down pin" Avenger E710, and more expensive than the cheap brass types) which makes the solution less than ideal. There are also safety concerns of course as I'd prefer to have everything tightened off properly.

A safety chain doesn't resolve the safety issue as I need enough slack to easily adjust the light and this slack allows the light to fall to far before being stopped by the chain.

I can of course lower the boom, loosen the light, turn it, tighten it and re-adjust the boom - but I'd rather just grab the light and adjust.

What I'd like is a fixture that will allow me to fix securely to a vertically hanging spigot, but will also allow a secure turning action to allow me to point my light left and right. Viewfinder Photography make such a fitting for their rail systems but alas it's not available as a standalone part.

I've been looking at Avenger swiveling adapters such as F830TH but these seem a little over engineered for what I need.

Any thoughts...?