Tom, I've written several articles about the X-Terras, so I am not quite sure which one you are referencing when you mention page 2. However, let me give you my take on the specific items you asked about. Auto GB is available on the X-70 and offers the user the choice of allowing the detector to automatically set the GB level for that particular location. To me, it is a short cut to manually pressing the up and down arrows, in an effort to find a point that the high tone and low tone offset each other. Remember that it may be difficult (and sometimes impossible) to completely neutralize the tones while adjusting GB. The Auto GB does that for you, with extreme accuracy. However, being somewhat old-school, I still check mine manually when using Auto GB. Keep in mind that when you use Auto GB, just as when manually balancing the X-70, the mineralization levels may still vary as you search. So, regardless of which mode you use, it is a good idea to check it every so often as you hunt. I try to check mine every 10 or 15 minutes. If you find that the ground mineralization at that site is fairly consistent, then you might not check as often as you would if you were changing it every few minutes. If you do find yourself changing the GB setting, in order to maximize the potential, you would be better off using the Track feature. Tracking allows the X-70 to continually update the GB setting, allowing the X-70 to obtain maximum depth of detection.
The Prospecting mode was designed to provide the most depth of detection and sensitivity for those who hunt in heavily mineralized soil. The Prospecting mode has an Iron Mask feature (0-20) that allows you to discriminate out certain sized ferrous targets. The lower you set the Iron Mask level, the smaller the targets are that are rejected. For example, if you set the IM level to 20, you will reject large iron targets but still allow small iron nails and bits of ferrous trash. The Prospecting mode works well for those hunting gold, but I find that I can use it for pinpointing as well. Personally, I hardly ever use any detectors pinpoint mode. Xing over the target usually gets me close enough for the sites I hunt. However, with the larger coils, I sometimes need some help. I don't often use the (non-motion) Pinpoint mode of the X-Terra, as the modulated tone and volume slow down my hunt. I would prefer to either X the target, or use the Prospecting mode. By simply pressing the Mode button, I am switched from my normal hunt mode to Prospecting. Prospecting mode does not provide numeric target ID, but I already knew what the target was before I decided to pinpoint. Instead, prospecting shows me the Iron mask level, and the audio allows me to center the coil directly above the target. And, it allows me to get an idea of the target size. Since I started sizing the targets in this manner, I haven't dug any of those darned mashed aluminum beverage cans. All in all, I find the Prospecting mode to be a more productive way for me to size and locate targets than the normal Pinpoint mode.
You asked if the X-70 can reject the rectangular and beavertail tabs and still hit on some nickels and gold rings? The simple answer is yes. It has the ability to reject certain pull tabs and still accept certain valuable targets. But you have to realize that it is impossible for any detector to reject all pull tabs and at the same time, accept all gold rings. Maybe the Explorer II, with the ferrous and conductive readings can be fine tuned to be more precise than most. But for notch type detectors, the X-Terra 70's two-digit notch system does as good as any and better than most. But, there will always be exceptions. For example, with my X-70, an unbroken pull tab bounces between 16 and 18. A square tab with a hollow top hole reads 26. A square tab with a solid top reads 24. A big tab that is flattened reads 20. A Pepsi screw cap reads 28. A mashed screw cap reads 30 and a
