I have about 2 inches before anything starts to happen on mine! I took the control box to bits because it is v v stiff as well, took one look at all the gubbins inside waiting to go sproingggggg all over the deck and put it back together again very carefully
Likewise quite a lot of play in my steering (probably about an inch, maybe inch and a half of slack at the rim of the wheel, before the engine starts to move), it would drive you mad in a car (and probably be unsafe) but it seems "normal" in the cable steering, nothing I can find that is wrong...
Now all I need is somebody to say "aaaaagh that is dangerous stop using it immediately" - both used to worry me but I have got used to it and after about 100hrs of use there seems to be no change and no problem.