I think that the default Z-values in the config (40, 60, 80, 100) are valid if you are using just a bolt to fasten the belt ends. Then there is no space between the spoil board and the belt ends. When using the 3d-printed anchors, there is some extra space between the spoil board and the belt ends. The belts are then a little (about 9 mm ?) closer to the arms so you could adjust the Z-values for this difference.
I have raised 3 of my anchors so they are now all at different heights:
For this setup, I used brZ = 34, tlZ = 38, trZ = 30, blZ = 26.
I found that the sled is now a bit more resistant to tipping over as the sled comes to the left side of the frame, but it did not make a big difference. I didn’t dare to make the anchors even higher, because the sled could then be pulled away from the frame.