I am looking for advice from the GPX Veterans on the forum. I recently acquired a GPX 4800. The stock coil with the 4800 is the 11" DD. I am thinking that my approach to learning this machine should be to read as much as possible about the settings, and log hours detecting. Not really a novel approach. So should I buy a mono coil now, or wait til I get more experience with DD? I have a feeling that at this point along the learning curve I may not even be able to tell the difference. Luckily I