I usually run disk 1 thru 9, in town I run 65-75 sensitivity and up to 90 in rural areas, no notch, 3 tone in trashy areas and 3H in less trashy sites. My main coil has been the nel sharpshooter, but have used all four coil in the past 2 weeks while hunting a 1900 permission. Dug a lot of clad, and a wheat using the sharpshooter. My last hunt there I finally pulled a 49 rosie using the stock coil. Must of been my swing angle that helped hitting that coin because I gridded this area using the sharpshooter a week earlier. I mainly use FA or DE processes depending on target density. I have been lucky to have carte blanche at many permissions, where I can grid it in multiple directions using many coils over time. The reality I face here in my area is that people have been detecting since the 1970's so most of the easy stuff is gone, yet I do run into a virgin yard occasionally. Most of my last keepers have come from trashy areas of permissions that were hit by others in the past. You seem to be doing great using each of your machines. I tend to concentrate on one detector, but my 3 land machines are all fishers and they are easy to swap since they all give similar target IDs. I dig most everything with a solid or tight target ID (within 3 digits i.e. 41-43) sweeping over in 2 directions.
GL & HH