Good question. How do these devices work with a challenging environment? I have closely spaced #5 rebar, approximately 6 inch on center AND this pad is placed on a Vulcraft metal deck. I sure would like to drill through and miss the rebar...
I have employed a company to do this for me in the past. My recollection is that it was pretty precise. If they aren't confident in their ability, I doubt they will try. Too much potential liability to take a chance.