It appears to me that you have a lot of variability.   If you have access to equipment that can variably rate apply your needed nutrients.... that would definitely be the way to go.   Even with the cost of having the work custom applied, I think you would be profitable to do that.  

Work on PH first.   Apply lime to get the PH somewhere between 6.5 and 6.8.   Unless you're growing alfalfa, then I would want the PH to be a minimum of 6.8.   If your base saturation Mg is at least 12%.... I would use high cal lime to get your PH to the desirable level. 

Phosphorus to 50 ppm
Potassium to a minimum base saturation of 4%




gordon