In this paper single domain, bulk SmBCO samples have been fabricated successfully in air in a top-seeded melt growth (TSMG) process using a conventional chamber furnace, in addition to samples doped with ZrO2. In order to improve the reliability of seeding, Sm-123+ Sm-211 mixed-powder buffers were used to increase the success of the SmBCO single grain growth process. SmBCO single grains of diameter as large as 20 mm and 10 mm in thickness with and without ZrO2 were fabricated successfully using Sm-123 + Sm2BaCuO5 (Sm-211) mixed-powder buffer layers. The geometric configurations of the buffers were also optimized as part of this study to further increase the success of the single grain growth process. Superconducting properties of Jc and Tc of the specimens under the buffer layer have also been investigated.