We use 2 ply construction on all of our tracks for better durability and reliable performance. Some manufacturers offer 1 ply to save money by eliminating a layer of fabric and rubber. Less material = less cost but you cannot eliminate a component of the track and keep the same long term strength.
We also offer full metal clips on all trail/crossover models for increased performance.
So to answer the question, we will be slightly heavier than a 1 ply track but feel the gain of less ballooning (stretch) and durability outweigh the single ply features for the majority of snowmobile riders.