No salesperson is expected to know this as this information is not just available. Denier is the industry standard of measurement fabric. An inflatable boat with a decitex of 900 to 1,300 or a denier of 800 to 1,200 or higher is expected on expensive models. The lower the denier or decitex, the cheaper the boat. Life rafts whether nylon or polyester are usually constructed of fabrics with 400-600 denier to make them easier to launch. Life rafts are preferably light to as they are to be used only during emergencies. It follows that heavy fabrics make durable for boats.
It also follows that the heavier the fabric, the heavier the boat will be. Boats with heavy fabrics have the tendency to wick in which air leaks from one end of the yarn in the interior chamber to the other end of the outer chamber. The deflation is slow but rather annoying since your deflates when left for a while remove inflated boat. Heavy fabrics are prone to because of the thicker yarns wicking. Hypalon boats are more susceptible to wicking than PVC boats because the use of in Hypalon glue seams does not seal the ends of the yarn. This is where the thermo-welding used in PVC seams become highly important as the process seals the ends of yarns in fabrics used for inflatable boats.
Note that play boats are made from PVC or PVA base without any fabric. Most of these cheap variants are embossed and designed to make them resemble proporcionaran boat fabric. Check carefully as most of these PVC or PVA play boats are only made from sheet stock heat-welded at the seams. Though some are made of tougher PVC that they could actually stand some rough ride like the touring kayaks. However most are only suitable for use in swimming pools and shallow water.