Hello everyone,  I live out here in the Arizona desert, and would like to know if anyone owns, has used or uses one of the SEF Excelerator Butterfly Coils, or the Whites ULTIMATE 13" coil available from Kellyco?  I would like to know what kind of track record these coils have for nugget hunting - do they do well with the high desert mineralization, or are they primarily for areas with low to medium mineralization?  I watched a You Tube video with a guy showing how his MXT works with both the stock 10 x 6 elliptical nugget coil and then showed what his SEF Butterfly coil can do, and the SEF coil did much better when it came to seeing through a highly mineralized brick to detect the nickel beneath it.  Anyway, if anyone has any advice pertaining to a GREAT "HOT upgrade coil for nugget hunting with White's MXT's, PLEASE pass it on to me ASAP - I greatly appreciate it!!!