you can edit your comments with the edit button under your icon if you ever make a mistake. sorry I dont know anything about the grids you refer to, just thought i'd help you with that :)
Basically you use the "Pattern Overlay" function under blending options in photoshop. You can create your own pattern to use with this, but I can't remember how at the moment.
"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." Bertrand Russell