Time for a new clutch?

Just my opinion.
Could it be that “Maybe” you have lost your reference point from the start?
As you say you have messed about with it loads, adjusting it up and down etc etc.
The main symptoms (plus others) of a worn out clutch are that it will slip under load/acceleration.
If yours is not doing that, its perhaps the time to go back to the basics.
From what I know and have read the NC clutches are quite robust.

Also plenty of threads on here about topping/checking the gearbox turret oil which seems to solve some of the issues. Mctrucky posted an “Excellent” thread on here yesterday.
His car is a 2008 2.0 and basically the same as yours. (Can’t remember the mileage).