Hi Dave:
First and foremost..I do not use, or own a DFX..............I use a XLT.................I think, and know Larry(IL) can confirm, or state if it just isn't the same on DFX like the Xlt has 190 pickup points factored in -95 to +95. This is really notch discrimination..Though Whites does not call it notch. You can never take out all pull tabs, and if you desire ring finds, you would not want to. Rings and pull tabs are very close on the scale. You can however remove the most common, and pesky ones from your immediate field of hunting. Say you dig 10 signals and it's a certain type..go to your learn-reject program and notch that tab out. You will still pick up other types, and maybe even some of the ones notched out..(Deep) whatever reason..But mostly that type will be gone where you are.It will help a little
and remember you will also mask targets near where you take out the tabs..So you can, and in fact, will loose some good targets in the process. The plus side is you can hunt, get most rings if they are there and cut down on the pull tab digs..It works most of the time well, and lets you hunt a really littered site.It's not the perfect solution, but at least you can hunt the area fairly well,and still get most of the keepers. I will restate...If you want rings..you must dig pull tab signals.
I have been informed for every 1,000 pull tabs you may find one or two rings..you have to decide is it worth the digging..For me it;s not.....for many it is.
The above is only my opinion and may not even be close to correct..so anyone with more knowledge please correct me..I welcome it.