Located also in central SC I usually use these guidelines for early splits..
1. average out all my hives first. I find i usually have hives that come in threes (strong, average/or par or growing, and dinks [that are surviving but still need to be evaluated before i make a change]). i also want all my hives to be 'even' so that i know whenever i visit my yards the following is true - all hives started the same, which ones are growing or need to be adjusted, and determine/confirm that the queens i want to breed from have still maintained my expectation over the winter. it makes management much easier if you can try to start each yard with the same type of management that way whenever you revisit them in a few weeks, you can quickly determine which ones aren't going to make it.
2. increasing my smaller nucs that need it first. by this i mean that i might take some brood from strong hives and supplement those 'known' good nucs so that i have 'even' configurations through the yard. I'm eager to make splits but would rather strengthen up a good/small nuc and make a split later from it then create a longer recovery time for the strong hive...just to make a split.
3. I use the old farmers almanac as a good resource for predicted or upcoming weather patterns - especially if i'm making walk-away splits.
4. 'if' i'm making walkaway splits - what age are my drones and how many are in the area (mine and others that might be around to contribute). I've always heard that if you have purple-eye drones that you can make walk-away splits but personally I thinks thats a little soon based off of the drone timeline for growth. I like to see some walking around and know more are to hatch quickly before i graft or make walk away splits.
5. 'if' i'm making walk-away splits i usually also wait until the weather has passed for frost. in my micro-climate, i usually get a frost by the end of february - just whenever the maples are starting to pop.
6. if you have enough brood and bees to make a stronger split then you can adjust as needed but I don't usually start before March 1. That said, i had to make 4 splits on ground hog day last year due to busting hives and many drones. of those 4, i still have 3 hives.
7. start feeding syrup to supplement and excite the bees for spring. I also use dry pollen year round at my different yards that way i can keep track of when the pollen actually comes in. SC is a good state in that it produces pollen year round, but also just because there's pollen - a good dry pollen sub available will (has in my case) make a world of difference.
As everyone knows beekeeping is not only regional but also should be considered a 'micro-climate' environment. I find that i have differences in pollen and nectar with hives that i have in different yards within a 10 mile area. Only you can determine from your history and climate when a good time is to get cranked up. I've heard all the tales and fell susceptible to them in my early beek days that you need to split by X day or they were going to swarm. I have friends that live about 30 miles away from me that see the pollen/nectar changes as much as 3-4 weeks ahead of me so if i used those 'hard dates' to make my splits - i'd be in trouble. As far as early queens - I think you've heard that pretty much the west coast or hawaii is the 'earliest' place to get good queens. I know there are some in lower georgia and florida also available in late/early feb/march times.
good luck -