If you get down on a really deep target, a vlf like a goldmonster can be used to pinpoint the target. Trust me, a vlf with a tiny coil has helped me save quite a few large deep gold nuggets from being damaged by my pick. I would get a 14x9 coil and skip the other. In my opinion the 14x9 is the best all around coil for everyday detecting. It covers good ground, get into tight places, and hits on deep targets. Find some gold, use your detector and then see if you want another coil. I would stick with the 4500 and the goldmonster.