Sure -
I use full tones basically when I am not too worried about thick iron affecting non-ferrous targets and when the ground is not too mineralized. Basically, whenever I am coin shooting but looking for deep coins or when relic hunting and there is not a lot of iron. I don't like to use full tones if I have to apply any discrimination because I like to hear the iron and iron volume DOES NOT work in full tones. If you disc out iron in full tones, you can no longer hear it at all regardless of the iron volume setting.
I don't apply discrimination to NOT hear iron, I apply discrimination to keep iron from interfering with non-ferrous target id and when I want the horseshoe icon to work right. I always use some level of iron volume when in discrimination mode. So, whenever I apply discrimination I am either using pitch in thick iron as sort of a two-tone mode (i.e., pitch and iron volume) and I am NOT trying to go deep. I am just trying to separate out masked non-ferrous and trying to NOT let the ferrous down average the displayed non-ferrous target ID. Note that in pitch mode you cannot get any idea what the target id is audibly (there is no tone ID in pitch).
If I am using discrimination to filter out less thick iron or want to set up special tone breaks to cherry pick specific targets like silver or mid-conductive relics, then I will go with multi tones (usually 5 if coin shooting or 4 if relic hunting).
Finally, in real challenging mineralized soil I will use gold field, it is the deepest mode available but basically you are sacrificing target ID altogether (it is also a type of pitch mode, but does not use traditional iron discrimination, it uses iron cancelling but even that does not work well in highly mineralized soil) and just going beep dig at that point and digging any repeatable signal.
Hope that helps.