Nissan Primera P11 TPS

Had abit of a look at my TPS recently and checked the voltages, 0.66volts at idle position and 4.1 at full load. Thought I would try to drop the idle to about 0.5Volts thereabouts...  Is that the recommended about 0.5volts? So I adjusted the position by loosening the two screws and rotating ... However now I can only get an lowest idle of 0.8Volts, higher than the idle I did have of 0.66volts! This is at lowest adjustment possible using the rotation setting.
Whats the trick to get it back down into lower figures (aiming for 0.5volts) now I have disturbed it somewhat? Presume where I loosened it and inspected it is now sitting slightly differently hence the higher reading -As right now at lowest adjustment that the rotation mechanism allows gives 0.8volts rather than maybe 0.3volts which would maybe be about right then I could rotate it abit to gradually increase to the desired 0.5volts thereabouts.. why has it increased to 0.8volts at the lowest position?
Is this just because I have disturbed it by taking it off/ cleaning it and now on re-assembly the position is slightly different from what it was?
Is there some sort of trick/ method for getting the required ranges? As right now mine is too high an idle and do not seem to be able to rotate it any more to lower it? Is at the maximum rotation poss and still gives 0.8volts? How can I lower it?
 

Think I am possibly putting the TPS into place incorrectly - it kind of sits on the pivot arm which operates it as the throttle is used. It needs to be abit underload from the arm to get the 0.5v reading at base but for some reason the way I am positioning it is getting more load, hence the 0.8v. I think am maybe installing it in the wrong position and the pivot arm is not in the correct position on the cam of the sensor. It seemed odd the way the sensor sits/ fits on the pivot arm. Will have another go at positioning it on the arm, expect it sits in a certain way and is a knack to putting it in the correct position, which I haven't quite and it is 'pinching it up' under more load and giving me the higher reading.
 Is there a knack to positioning the sensor on the pivot arm in the right position? Seems abit odd the way it sits?

I managed to get the voltages lower (0.58v at idle) eventually, after abit of messing about.
However not in the way of rotating the sensor. By just rotation of the sensor, it would not go below .80v but there are some tensioners and adjusters on the throttle that you can adjust to take the tension of the spring load on the TPS. So, I got it down to almost the exact settings in the end.
Car does run and idle smoother now than it did.

Yea-Brian, probably wouldn't/ shouldn't have touched it other than I thought the 0.66V when I first put multimeter on it, may have been abit high- did not realise though that it would turn into abit of a saga with this much messing about just to get it abit lower! Think it would have been alot easier if it was within the ranges by rotation but it wasn't, hence the issues! Oh- well- it does seem to run smoother now though.