Ralph, have been following this thread and appreciate everyones input and the responses respectively. What I want to know is because the nickel has been moved up into the high tone category along with dimes, quarters, bottles caps and a few other items how are you being able to distinguish between them. The dimes and pennies I see no problem since the VDI numeric will take care of it, the same would probably apply to the nickel since it too though in the high tone range will display a VDI reading of between 56-57 though have picked up a few at 58. The one that is really giving me a fit is that of rusted bottle caps. These all seem to jump up into the quarter range and will read as such. I have noted that by watching the FeO4 bar graph and if I see two or more bars reading from the bottom of the graph upwards, you more than likely have a 80% probability of it being a rusted cap. Other than this method, how are you going about identifying bottle caps? I did find too that if you disc out everything (set the sens at 80) and use the three tone audio there will be a distinct clicking noise when making a pass over a rusted cap. One other thing too is that if you raise your coil slowly you will find that you will lose a quarter at approximately 8-9ins though if a bottle cap you will still be able to pick it up to about 10-11. Just want to know if you or any of the others have found a better way of identifying those pesky caps.
If they're not rusted I can pretty well get a handle on them, but the area I have picked out to perform most my tests on is relatively old (dating back to the late 40's) and has lots of trash. The area is great though in that it is right next to a river/lake so I also have sand, clay, loamy, humus, soils to work with. There's also a playground within walking distance that I can easily enough stroll over to to play in the woodchips. Well if you guys ever figure it out let me know. Right now I have approximately 139hrs on the unit.
The reading tends to read a bar low until you pump the coil over a clean spot to get the more accurate sampling. In this regard it is something akin to the ground balancing routine.
I spent more time trying to figure out small signal falses than anything else. Luckily I was able to switch out coils and eliminated that problem. Thanks in part to your posts. You didn't seem to be having any problems, so it made me think something else was going on. Turned out I had a bad coil.
Only thing is now my time is limited:sad:
In regards to battery life I would hve to agree that they will last as advertised. My first set lasted 47hrs, second set 41, third 43, and now I am working on a fourth though this set is rechargeables. I wanted to see if it would affect performance and though I have only had them in the unit for the difference between the 131 total and what I have put on them since the 139 mark they seem to be working well. They even showed as adverised when put in there like they were only half charged. I wanted to see how fast they will discharge as compared to the alkaline. 
Yesterday I was able to put in about the same amount of time though only out 1.82 since I was really just testing audio responses more than I was looking for targets. Overall I think I am getting better with the unit though still feel like there is much, much more to learn to get it to work at it's fullest potential. Like Mike I want to find out what hidden capabilities this unit has. I have never seen a unit that will only do what they say it will. If various tricks/skills are applied during the hunt I believe one can easily take any given unit to the limit. IMO this unit has much more potential than what is in the manual or being advertised. Still can't wait to try it on the salt water beaches. Well lemme go and let me knwo how you two are doing, all lessons learned are appreciated.