Both are practical neutrals, but they do different jobs. The Plain Classic is a true sheer with a natural-fiber feel (cotton, viscose, polyester) at 148 GSM - lighter and more transparent. The Softlight is a denser 100% polyester light-filtering fabric at 189 GSM - more privacy, more glare control, smoother surface. If you want a warm, organic feel and maximum daylight, Plain Classic in Dove. If you want meaningful privacy and softer light quality, Softlight in Dove. Both work the same way for layering with a blockout behind.