What we do is I put myself roughly 2-3 CAR LENGTHS away from a wall, and my dad puts up a white sheet (BE LEVEL!). I turn on the high beam and orient the beam. With a YVRMK2 you can see the center line, use that as your guide. Done right, when you go low beam it'll be just right. (Best to do it while your sitting on the bike and the bike is also leveled up)
Not sure if it works with all H4s, I've got a H4 Phillips that I am SO throwing away, and getting something better (and aux lights... I want to ride at night.... want... want... want.... but can't..)
Around here, its not other motorcyclists you have to worry about blinding you.
Its the drivers. No one seems to know how to align their lights properly for any vehicle they drive, except for semi trucks... for some odd reason those are 9/10 correct....... better than cars 4/10 or trucks 6/20.