Foggy I am in heavy river bottom gumbo ground and I have to say my axle hole number correlates very close to this chart and it's corresponding depth results
What the chart cannot do in my opinion is account for soil type as well a soil moisture content ..therefore I consider it to be very much like numbers on a toaster in which you will "proof" for ALMOST each of your fields as to soil type (in my case my drill set for my bottoms will not please me on my ridges) ..add to that moisture present in the soil so ...
Not only is data (drill settings) maintained on the different soils but also moisture must be considered
Hole seven on my bottom ground gives me 1/4" bury on the main box with 60# of air maintained on the drive wheel
Bear