Hey there, some update:
I applied some chapstick(-equivalent) to the knife edges and re-assembled the unit. I could not detect a real change in my wandering tuning issue, and overall tuning stability was still poor.
I then followed precisely every step in the lockup procedure from IR and yep, it helped me getting it to a point where the tuning shifts were quite predictable at least. But I realized a new problem, that might hint to the actual problem:
When I got it in the low neutral, stable position, it kinda stays in tune. When I do a big bend on the high E string, the tuning shifts drastically. E and B go flat by a remarkable amount, and low E and A go flat by up to 7 cents. When I then do a whammy down, it returns almost exactly to low neutral. I know what you think now, but what I reach through bending is NOT high neutral, it has a different pattern. So it is kind of a third neutral point and I have no idea how it comes to be.
Interestingly enough, I have not been able to replicate "third neutral" by for example pulling the E string, by moving the E string sideways in its saddle to find a crack or something that it might slip in, pushing down the String behind the nut to see if it is not locked properly - no way. Stable, until I do a bend?!?
What I did then: Order two new posts. They arrived today, and after chapstickin' I reassembled everything. Result: Slightly reduced wandering tuning, but exactly same behaviour when it comes to the bending problem. Sigh.
Why have I not pulled the anchors yet? 1. I could not detect movement 2. I don't dare to really
, is there any procedure with pictures? 3. The fact that neutrals exist makes me doubt that the anchors might be the cause.
Sorry for my long blabla