Can anyone give me some input on coil size as related to depth? Does a larger coil read deeper. I recently purchased 10" and 4" coils for my BH3300. I hope the 4" helps in a couple of trashy areas that I beleive will yeild some nice stuff. Will the 10" give other advantages besides a greater area? Thanks Howard. P.S. They arrived today and I'm hoping to try them out this weekend.