The R/L centering is difficult w/o the wall geomerty and that adjustment is critical , being that they are independent..

A good place to find a wall where the pavement is also level is behind/side of any small strip mall...

Give a friend a couple pieces of black tape to hang at the two final spots on the wall and , using your blanking towel, do each one and then remove the tape from the wall and take a ride to see how you like it . The reason for the varient of 2-3 inchs on the cut-off height is to give you a little high beam up/down preference ... just make sure you never have the cut-off ABOVE the horz line....
I personally use 2 inch drop at 10 meters....full tank/gas