Hi, I'm new to this board and I don't really know alot about metal detecting, but... my husband loves it... I would like to do something nice for his birthday and maybe get him a new coil. I have his Kellyco magazine in front of me and I see two coils I'm interested in. Their both Excelerator searchoils, one is the 14" coil and one is the 16.5" coil. I was just curious if anyone could let me know which coil would be better. He mostly hunts old house foundations for relics and old coins. I would like to get something for him that has a little more depth and can cover more ground, but I'm really at a loss in regards to which of these coils to choose from. Can anyone help???