First, fitting an emergency tiller might not ever be easy.
Whatever anyone here thinks of Cruising World's Boat of the Year, one of the first things the judges do when a boat is under way is under way is get out the emergency tiller. Interestingly, the builders and their reps seem to have got this message . . . the tillers on the tested boats are almost always right there inside a locker and usually in a proper bracket..
Next up is fitting it. That's easy enough when someone has hold of the steering wheel and is holding the rudder steady . . just drop the tiller over the head of the rudder stock. Probably not so easy if the wheel is disconnected from the rudder . . and especially in a full gale.
Next is to try to steer with the emergency tiller. Most of them are just too damn short for bare hands. To use one effectively, you have to rig lines from the tiller to the winches.
Now try putting all those pieces together with someone overboard and the two remaining on board trying not to lose sight of him while getting the boat under control. And where was the third guy when all this happened? Sleeping? He has to drag himself on deck into all that chaos.
Now for Dave and big wheels. I'm not surprised you can't steer straight from the rail. When you stand behind the wheel, you can sight over the bow and aim for something. If you're sitting out on the rail and sight over the bow . . . you are not steering toward whatever it is you're looking at. Little matter of parallax.
I wrote an article about this for CW . . but based on twin-wheel boats, but it's the same problem. The inspiration for the article actually came from trying to steer a catamaran with an offset steering station.