I just purchased the exterra 70 pro pack with 9" 7.5 coil and the 5x10 18.75 coil I own an ace 250 but wanted the upgrade so not very familiar with the machine. Live in mn so havnt been able ti use it yet other then air testing with some coins. Going to south texas at end of month and planning on detecting south padre island not sure what coil would be best?? and should i hunt in beach mode only?? also noticed while air testing with my clad coins the numbers jump around a little bit is this a sensetivity issue or??? any help would be appreciated also if anyone has detected south padre any hints there would be appreciated too never been in that area before Thanks Don