Deus and GB:
Version 4 gb Tracking is much improved over Ver 3.2 GB tracking and I set it there and forget it for 90% of my hunts unless I am in an area with wild swings or highly mineralized, then I keep an eye on it and maybe just adjust manually on the fly. One of the drawbacks to GB tracking in ver 3.2 is that it would lock on to ferrous targets in the ground as you swept the coil and eventually those targets would disappear because the tracker upped the Ground Balance setting based on a perceived higher ground conductivity reading. The new tracking algorithm does not do this.
I think keeping it at 90 (manual) in mild soil is probably just fine, but be careful about making the decision based on it "running quiet there". It will run quiet if you bias GB high and as a result it is akin to lowering sensitivity therefore keeping GB greater than about 3 to 5 points ABOVE actual Ground Conductivity/Phase reading as indicated in the display COULD cause you to loose some depth.
People like to pump the coil to "semi-automatically" adjust the GB setting, but there is nothing wrong with just manually punching up the GB setting so it matches the reading. No real need to pump since the actual Ground reading is continuously being updated.
Some people actually like to make the machine run hot in an effort to boost depth by intentionally biasing GB to 3 points BELOW the actual ground conductivity/phase reading. The machine will of course get chattier but you might also hit on a faint deep target that way.
Andy Sabisch and I originally thought that XP would provide a tracking offset setting to accommodate "hot" biasing the GB setting continuously, and according to Andy, it was actually included in an early version of the V4 software but they decided to eventually scrap that feature later for whatever reason.
Another GB expert setting is ground notch which can be used to get rid of hot rocks by biasing out the signal (again a sort of filtering/discrimination) applied when ground reading is detected within the range of the "ground notch". Some folks recommend just notching out the entire range because it tends to quiet the machine down from a ground feedback noise perspective, the problem is that other folks have shown that doing so will (not surprisingly) affect depth in SOME cases. YMMV.
HTH
