Help, please, adjusting H-1's
 

There are 4 adjustment screws on the H-1 headlight - 2 near the top, one on the outside of the headlight rim, one on the inside, and 2 towards the bottom, again "inside & outside" of the rim. Please advise as to which screws adjust the beam vertically, which adjust the beam horizontally, and is one set for the low beam bulb and the other set for the high beam bulb? MANY MANY thanks in advance!