The Darlin Marion Tuttle (1780-1846) is the Darlin Tuttle in the 1830 census for Clermont Co.
His son, the Darlin Tuttle (1809-1865) who married Rebecca Swift in 1828, is the Darlin Tuttle who appears in the 1830 census in Butler Co. Ohio. This Darlin Tuttle also had a son named Darlin Marion Tuttle (1838-1919).
Moreover, the Darlin Tuttle (1809-1865) had a brother John Smith Tuttle (my ancestor) who also named one of his sons Darlin Marion Tuttle (1841-1932). This last DMT married Susan Lake in 1858 and named one of their sons Marion Tuttle (1870-1919)
Hope that this helps. However, it doesn't do much to help us find out where or when the name Darlin came into this family!
Good hunting! Sharon