I am going to be cutting a 12X12 inch square hole in a concrete slab to accommodate a drain box, and was hoping to get some cutting tips from you who have done this before. I am going to get a diamond blade for my circular saw and cut the hole. Which blade is better :wet or dry? I guess with wet I would keep the area wet with a hose trickling water out. Am I correct? What about depth of cut? I cannot see going 3 inches all at once. How deep should I set the blade for each cut? Any precautions to follow when doing this (outside of the obvious of gloves, eye safety gear, filter mask)? Thanks.