OKI ES9431 - Print Adjustment and X,Y Centering

Hi, can anyone explain to me how to adjust the print centering with respect to the sheet and on both sides?
1. If I make the first X, Y adjustment, do I adjust the offset based on the correct front?
2. If I make the second adjustment for both sides, how does it work? Is the X, Y offset the same on both the front and back?
And let's say it shifts 5mm on the front and 8mm on the back, how do you adjust the 3mm offset on the back by adjusting the XY axes?
3. I've currently managed to get a few millimeters of offset on the front and back, but I've noticed that the difference is that the print on the short side (the gripper) is not parallel to the edge of the paper.
For example, if on the left side it is 5mm from the short side, on the right side it is 8mm, so it is oblique and not parallel to the edge. (5.8mm distances are purely for example). So how do I adjust parallel printing?
The paper in question was a 130g matte coated paper.

4. Y Scaling -0.25%, what does this adjust? Does the manual say image zoom? Or rotation?