When purchasing Rayon Grey Fabric (greige fabric), you must prioritize Yarn Count (e.g., 30s, 40s, 60s) and Thread Density (Ends Per Inch/Picks Per Inch), as these determine the final fabric weight and hand-feel. Ensure the GSM (Grams per Square Meter) tolerance is within ±5%. Additionally, verify the pilling resistance and tensile strength, as rayon is known for being delicate when wet. For high-end applications, specify the use of branded fibers like Lenzing Viscose to ensure superior uniformity and fewer weaving defects.