Personally, I like the Original Gray Ghost Headphones. I have used quite a few different models and like the fit and feel of the Gray Ghost. Very comfortable and I can wear them all day. I also hear good things about the Koss 9000 phones. Also well padded and quite sensitive. I have the set of Royal White's that came with me detector, but they are smaller and not as comfortable to wear. Guess the size of your melon will determine what fits you best. Most coils are waterproof, but some are only water resistant. Make sure you know the difference before you dunk yours in the stream. Don't get the detector housing wet and be careful not to raise the coil above the housing when you take it out of the water as some might run down the inside or outside of the shaft and get into the electronic components. If you are careful, you can hunt around water with the machine. As to coils, depends on what you are looking for. The MXT comes with a 9.5 inch concentric coil that serves most people well. Some of us, however, always have to tweak things a bit. The DD coils are better in mineralized soil. The 5 inch seems to be getting lots of praise. The small 3X6 Eclipse Shooter is a good choice for some. The 6X9 Eclipse is a good DD coil to replace the 9.5 stock if your stock 9.5 concentric don't work well in the ground you hunt. Since you are new to the hobby, the larger coils, including the 14 inch Excelerator, will go deeper than the smaller coils, but are heavier to swing and harder to pinpoint with. But many guys are making good finds with them. Just as with your JD equipment, different tools for different workers and different jobs. As to a test plot, anything you can put in there will help you become more proficient. First of all, clean the area out so there are not any objects in there you don't know about. This could drive you nuts later on. Varying depths and several feet apart, bury every type of coin and jewelry you can afford to bury. Siver, copper, gold, a ball of aluminum foil, old metal button, pull tabs etc. I have dimes at 3 inches and 6 inches. Quarters at 4 inches and 8 inches. Indian cents at 4 inches and 7 inches. ETC. By the way, put the gold flakes in a hard plastic case of some sort. Not a thin bag but a hard jewelers case. Make a measured drawing of the plot and put it in a safe place. Depending on your soil, the deeper targets may not be easy to find for the first few years. Metal oxidizes and bleeds minerals in the soil, causing what some refer to as a halo effect. Seemingly, a silver coin buried 100 years will produce a "louder" signal than one buried last week. Learn to listen for the signals of each target and use the VDI to confirm what you hear. Practice every chance you get and enjoy the hobby.