Keep in mind that Southern Yellow Pine can be any one of the following pine species: shortleaf. longleaf, loblolly, slash, Virginia, pond, table mountain, pitch, and spruce.
The preferred species for your application would be shortleaf and longleaf pine. Pick the boards with the tightest annual ring count (15+ rings per inch is best), and run away from any boards that have only 4-7 rings per inch.
You may have to ask some local woodworker guys for a sawyer as those businesses are typically very low profile.
