Groundbound those sound like sensible tolerances, I am not quite sure of the exact figures, I can see my trevor thom from here but I am not getting up to fetch it!
I always remember a little phrase that helps me, from my instructor actually!
'Never except second best'
Its as simple as that, if the dial doesnt say what you want, quite simply do somthing about it, 50ft maybe 50 ft, but its still not what you want!
Remember we are professionals now!
The four T's also help when making approaches, always go over the beacon, just a little to the side wont do, and start timing imediately.
TTTT (Time Turn Task Talk)