just upgraded from the xs to the explorer 2,now am considering a larger coil as i am getting a lot of deep weak signals.would like to get some extra depth.Am i better off with sunray,wot or explorer coil and what size.How much added depth should i expect toget.Are the aftermarket coils calibrated to the explorer electronics.I hunt mostly parks and local fairgrounds but they are not to trashy.Also are there really that many gold rings out there...i have so far been focusing on coins only.