There are six Youmans in the 1790 SC census:
Harris Youmans p13 Beaufort District 1/2/4/0/0 (wm>16, wm<16, wf, all other, slaves)
John Youmans p13 Beaufort District 2/1/1/1/1
John Youmans p99 Orangeburgh Dist., So. Part 1/0/2/0/0 (mixed in with clearly identified folks at lower three runs)
John Youmans, Senior p13 Beaufort District 2/0/2/0/0
Levy Youmans p13 Beaufort District 1/3/3/0/1
Solomon Youmans p13 Beaufort District 1/3/2/0/0
SCGenWeb - Hampton Early Settlers

SCGenWeb - Hampton County Surnames

SCGenWeb - Hampton County, South Carolina