Mary, I don't know how much help this will be, but in researching my James A. Sweat, I have the following on Gadi Sweat: On the 1850 census (I have the book), there is a Gadi Sweat 27 Laborer b.SC, Eleanor 31, Thos 10, and Benj E 3. These are on p149, Ln401. Then on the 1860 Index I found, there is: Gadi 40 SC, Eleanor 40 SC, Benjamin E 10 SC, and Thomas 20 SC. These are all on pg 203A Ln22-25. Then on line 26 of same page there is Nicholas Tally Sweat 8 SC.
I also found some notes taken from another posting made by Janice Sweat: Gadi (Gideon) Sweat b.abt 1820, and Eleanor Gillespie of Marlboro Co SC, had four sons: Thomas G b1840, Benjamin Ellis b.1850, William Rufus AKA Nicholas Tallie or Talley b.1852 and David Allen Sweat b.abt 1854. (David is 6 on the 1860 Index, same 203A pg, Ln27)
Janice is someone who probably can help you since you are working on the same line of Sweats. If she doesn't contact you through your posting, contact me at firstname.lastname@example.org and I will give you her e-mail to contact her yourself. Til then, good luck and I hope the above helps. . .Carol