Hey Jason,
I thought they used to have a video on their website on how to add screws to their Grip Kings, but maybe not. I couldn't find one just now. I did this about a year ago and it's pretty simple-- just use a drill with a 3/32" bit, drill through the holes/pockets where you want the screws, then screw 'em in! I was nervous to take a drill to my pedals, but it all worked out fine. I believe I put 8 per side, 4 front/4rear. Very, very grippy. I was trying to mimic the grip of some
Race Face Chester pedals I have on another bike and it worked great.
Best of luck!
Erik, Philly