Who has their cannas in the ground here in NW GA, please raise your hand? I want to get these babies in the ground, and don't want to learn from experience.

Well I am not growing cannas in NW GA, but growing cannas in your location is not much different than growing in IL. You will have a longer growing season and MAY choose to leave the cannas in the ground providing they are well mulched and not in a soggy soil setting (winter).
Cannas grow quite well in clay soil but these soils can present some challenges. Heavy clay soils are difficult or nearly impossible to work when wet; hard as a brick when dry. The clay tends to run together and become sealed and clump preventing water penetrating in the summer; often stay wet and tight in the winter. In other words, many clay soils are very low in organic matter. You may consider removing the top 6 to 8 inches of your soil and replacing it with a decent loam or something you would use in containers. You may simply mix plenty of organic compost into you canna bed. At the very least I would suggest that you lightly mulch the bed to aid in holding soil moisture.
Fertilizer needs are always determined by available nutrients of your specific location but you can always start with a light application of balanced N-P-K or what worked in your containers.
You will very likely have to deal with one particular pest of the southern canna grower; the lesser canna leafroller. I can only recommend the use of a good systemic insecticide if you expect to grow reasonably clean plants; otherwise your plants will suffer the results. Best,

Kent