I have used them a couple of times. A common issue is not having a good top bearing on the rudder
stock, so the rudder stock can flex. Another issue can be holding the tiller down, sometimes they want to work themselves up and off under load. A bolt or nut to lock it down to the shaft is reassuring.
Slop is a big problem. If they are too tight they dont fit, to loose and they slop. Ideally some sort of taper or clamping arrangement would be nice but I have never seen one loke this.
Its a very good idea to test it in nasty conditions. Its also a good idea to stow it somewhere handy. I like to lash or cable tie it to a deckhead so it can't be buried under stuff.
How do you stop water
leaking through the hole in the deck
? This can be a real problem in nasty conditions. And can damage autopilots mounted aft.