well for my first helmet I kinda just rigged it up, and unfortunatly I dont have pics of of what I did, but I'll make sure to take some of my next one. All I can say is use very small ones, maybe like twice the size of the screws that normally come on a pair of glasses. Really you can just use like 4 small screws and screw them in just at the edge of your visor so when its tightened the head of the screw clamps down on the edge of the visor, thus holding it place. You will want to position these screws so your visor cannot move up or down or side to side. Also, you will probally want to add some thickness to your helmet where the screws will go in, if the screw comes thur the outside of your helmet, no big deal, just file it down and add a dab of paint. I wish I wasnt so gimped with posting pics or I'd just draw a nice diagram. I know I saw a pic on this board of what I just explained so search around for visor threads. I hope this helped a little.