Other than using HELLA BEAMSETTER, vertical walls would be the easiest way.
It's almost impossible to simply adjust the angle through the star adjuster on the back of your headlight as each headlight assembly sits differently. Unless anyone else has a trick that I dont know of.
PS... JRE, sorry man, I havent had time to took off the fuel rail and take some pictures for the 'how to.' Perhaps I could steal some pictures off JasonH's site and write up a quick how to.