Hi,
I have just tried to adjust one of the jets on our 03 reg Micra that was spraying above the windscreen. I tried with a substantial needle, as I have done with other cars and, I think, with our Micra in the past. But the result was that part of the nozzle cracked off, so we now have a weak spray two thirds of the way up the screen! I don’t know whether I would have had a better result on a warmer day (it was just above freezing), or the plastic has become brittle with age and weathering. But be warned if trying to adjust old Micra jets on a cold day.
Chris