Double Pinch Pleat curtains are a beautiful way of adding detail to any curtain. The pleats are hand sewn and perhaps more effective than Triple Pinch Pleats on thicker fabrics such as velvet. I would recommend that Double Pinch Pleats hang below the pole to allow enough space to fall as they should.  They work equally well skimming above floor level or tumbling softly onto the floor.  In my own home I always interline them as I feel it softens the pleat and makes them look fantastically sumptuous, but they work equally well with cotton, blackout or thermal lining.