Chet, one more thing, but important.Martin and Rebecca named their first son William Blufford Atkins.William, you will recall, married Martha Anne, oldest daughter of Spencer and Milly.Both Rebecca and son William are burried at Atkins Cemetery in Caliborne Parish Louisiana.It was common in those days to name the first son for the father of the father!The problem is that both the William's in the 1810 census only had one son in the 10-16 age and none in the 16-26 age range. There was a third William in the Spartanberg District (p. 193) that had two sons in the 10-16 range, but none in 16-26.
A John Atkins also had two sons in the 10-16 range (Greenville Dist.), but no one in the census for SC in 1810 had sons in BOTH age ranges.Alas, nothing is perfect! So maybe Martin was the son of one of the William's and Spencer was a son of either the other william's, or Betsy or John.
I could send you a private email of the 1810 study if you like.Ed