Some folks asked for dosage information in the spreadsheet, so added that and called it:
N-P-K_Mix_Analysis_v02.xls.
As an example, you can get the citrus ratios of 3:1:2 by mixing:
4 lbs Blood Meal (steer)
1.1 lbs Bone Meal
0.7 lbs Potassium Sulfate
For a citrus plant outdoors in a 15 gallon pot, the maximum annual dosage would be about 0.8 lbs, which you could divide up into monthly or trimester feedings.
Keep in mind that this only covers the N, P, K ... there will be follow-on posts about obtain the minors, micros, and hormone ratios for citrus and other near tropicals.