I have done a little work in Fl about 15 yrs ago; and have pulled 10s of thousands of pine stumps in coastal SC, which is very similar terrain. I have run many Case backhoes of various vintages, and have owned a 580 superK for 10 years.
For 12-36" pines in the southeast, with a 580B, your strategy is going to be to dig a fishpond with the stump in the middle, then pull the stump out.
With my 45,000 lb trackhoe, I can usually shake and rock a 12-18" pine stump, then clamp it in the bucket and thumb and pull it. Bigger and I chop down to loosen the dirt and roots on all sides, then shake rock and pry; 36" stumps, I dig.
With my 580 superK, which is much more powerful than a 580B, I have to dig pines above about 10".
From being on this forum, I have learned that pines aren't that tough in other parts of the country, but in the southeast, they are one of the toughest stumps to pull.
Good luck, and have fun.
Mitch