I tried a Zircon stud finder on my plaster walls, without any luck. I need to find the exact location of my studs, outside edges and dead center. I'm putting up custom shelving, a loft bed, museum picutre rails and more. How about a radar stud finder, I can't find one to check it our? I don't want to make pilot holes in my plaster. My wife will kill me if I mess with here paint job.