I do not find Cyrus and Temperance Henderson having tombstones. They appear on the 1850 and 1860 census as you know. On the 1860 census, they were censused in the middle of people who lived in the Town of Cumming. I did not find them in the 1870 census. The heaviest Henderson burials were at Shady Grove (northeast part of county, not Shakerag), New Harmony (close to the Cherokee line) and Concord (close to Dawson county line.