Allright! I reopened the pumpkin...
After 100 miles the backlash went from 0.010 to 0.011 in, the contact patterns were about the same (see attachment).
I removed the additional 0.004 in pinion shim and adjusted the backlash to 0.008 in (result: see attachment).
Result: no more noise during acceleration or constant speed.
Nothing! from 0 to 90 mph absolutely no gear noise!
Coast: I (think) I hear some very little noise between 50-30 mph, nothing bad. It could also be the snow tires... It's during decelerations so I don't bother.
Looking at the contact pattern I have the feeling that DRIVE became better (bigger contact area) and COAST became worst (smaller contact area). This could explain the quite acceleration and the little noisy deceleration.
I'm happy with the result! This has been the last step to convert my A4 to a M6
This is a Yukon thick gear kit 3.42 ratio for a series 2 carrier, I ordered the parts from txdrivetrain.com (part number: YG GM 7.5-342T)
Jason made a grate price and helped me a lot with useful hints. The parts arrived 1 week after I ordered them: what a service! (also considered where I am).
Also thank you guys for your suggestions