1) The study investigates the nucleation and growth of c-parallel (c//) grains in co-evaporated SmBa2Cu3Oy films using scanning tunneling microscopy, x-ray diffraction, and transmission electron microscopy. 2) It was found that the volume fraction of c// grains increases with increasing supersaturation during film growth, indicating that kinetic factors like reduced surface mobility promote c// nucleation over c-perpendicular growth. 3) No evidence was found of a critical thickness for a switch from c-perpendicular to c// growth; instead, c// grains nucleate throughout film growth when supersaturation is high.