The steering system doesn't need any lubrication, except where you see the steel rods at the end of the cables. These rods enter a tube and you need to keep them greasy.
There shouldn't be too much slack in the cables...What too much means is when you turn the wheel and the rudder shaft doesn't turn after 5 cm (2 inches) on the wheel's circumference, then you have too much slack in the cables.
Then, you need to tighten the cables ' housings (just like on a bike brake's cable).
This happens in the aft cabin. You first undo the big hex nuts that secure the housings to the threaded tubes.
Then you turn both tubes clockwise (when you face them looking towards portside). To know how much you turn, carve a little mark on each tube.
Start with one turn on each tube, then try to turn the wheel and watch when the rudder shaft starts to turn. if you can still turn 10 cm before the rudder shaft moves, you still have too much slack. Then turn each tube half a turn and check again.
Don't forget to tighten the HEX nuts at the end of the operation.
You're right to mention that with a loose cable system, the pilot rotary drive is working half the time for nothing.
If you really tighten the housings too much, you will feel it when you turn the wheel, it will be harder.