Found this information on a Coats and Clark blog. Perhaps it will be of use to someone.
Thread Description Plys Tex Thread Weight
Dual Duty XP General Purpose 2 30 35
Dual Duty Plus Button & Carpet 3 104 10
Dual Duty XP Fine 2 20 60
Dual Duty XP Heavy 3 70 15
Coats Cotton Covered 3 30 40
Dual Duty Plus Hand Quilting 2 40 25
Coats Rayon Machine Embroidery (40 Wt) 2 27 40
Coats Extra Strong & Upholstery Nylon 3 70 15
Coats Outdoor Thread 3 90 12
Coats Cotton General Purpose 3 35 30
Coats Cotton Machine Quilting 3 35 30
Coats Extra Strong For Jeans 2 60 20
Coats Denim 2 35 30
Coats Polyester Bobbin 1 15 70
Coats Cotton Hand Quilting 3 50 20
Coats Metallic 2 30 40
Coats Transparent Polyester 1 15 70