.................has anyone tried the 8.5 inch Crossfire 2 coil on the GTP 1350? Would it work? I'm assuming that if the 4.5 inch Crossfire 2 works....that the 8.5 would work also?? Would it not make the detector balance better and feel lighter? What operational differences are there between the 7x10 Elliptical and the 8.5..........are they not both concentric? Has anyone used both of these........tell me what you found. Thanks.