yeah, I realise I had the wrong idea. However I was pretty sure I tightened the screw firmly. I checked this again and I had done so. All i did was "correct" a bit the clip that lifts the needle as it seemed twisted/stretched.
I made (sort of) the gauge and measured as in the photo ( middle bar resting on the lever) It is quite close. Close enough I would think.
On a side note, I can't help but think this tool would only be useful if I knew my lever had got the right shape. As I said, mine did not look so. Also if you saw the lever was too high, how would you adjust it. would you use a screw driver or something to bend the lever?
At this point, to be honest I am not sure what I should be looking for. It is true I have the feeling the mylar diaphragms made the cutter run slower but I could be wrong, and if not maybe that how it is supossed to run. I don't have much experience with one of this.
I will be interested in learning about the fine tuning even though I may not need to apply at this stage.
Thanks again for all your help, I had fun bringing the cutter back to life and more importantly avoiding it to go to landfill.