I believe 30 minutes is considered a legal connection in ATL. But have others have said, the later in the day you get, compounded w a holiday high volume day, the more the dominoes could fall against you. You might benefit from the tower holding CHS if there are others making connections to the last flight of the day, no other aircraft needs that gate, no curfew issues at CHS, then you get straight into your arrival gate, get off quickly, don't have to transfer through 3 terminals, etc....in other words, if all the planets align in your favor. Your arrival crew may or may not be able to provide information on connections, though I have had flights where that was done, i.e. DEN, relax your flight is delayed, CVG we're holding, but hurry, etc.

Bottom line, as Singleflyer said, don't dawdle. Good luck.