This is a close up of the Trapunto Quilting showing the puff obtained by adding the extra layer of batting.
By using Vanish-Lite by Superior Threads (available in 300yds. or 2,000yds.) you do not have a second row of stitching showing on your main design.
Because Vanish-Lite is a washaway thread it disappears when sprayed with water and is no longer visible as a second row of stitching.