A custom polo shirt is not a T-shirt with a collar sewn on. The collar height, stand, placket length and button spacing change how the neckline sits and how the chest embroidery lands. Brands that start from a basic tee block often see collar collapse after washing, a placket that twists, or a logo that sits too low once the garment is on a body.
Build the polo as its own pattern. Send a reference garment or clear photos, then list what must change: body length, chest width, sleeve length, collar height and placket length. Approve those relationships on a finished sample, not only on a flat sketch.