I didn't know that Dacron and polyester were one and the same thing. Huh. Learn something new every day.
Not a problem; we should all be learning something all the time.
In my line of work (like the pun?), I handle all sorts of exotic cordages, as well as cheap floating polypropylene, everyday nylon 3-strand, and run-of-the-mill dacron (polyester) double-braid. Smaller lines stretch more for a given load. So does 3-strand over double-braid, over parallel-strand.
So... the approach I've taken for my own boat is to use a good dacron (or you could use single-braid spectra, such as Samson AmSteel) pennant from the cleat through the chock, and then go with 2 lines out of that -- one very stretchy (for the "rubber band" effect), and one a little longer and more stout to overcome larger loading. Works well. Minimal chafe, easy motion, and secure tie-up at the dock.
For anchoring a bigger boat, I like chain, with a nylon snubber line at the boat end. For a small boat, in smooth/soft bottom conditions, the rode could be over 50% nylon spliced to a generous amount of chain at the anchor. A catamaran would call for a bridle to "connect" both bows together, distributing the load, and helping to keep the bows to weather. For permanent moorings for monohulls, we also use a bridle. In any of the scenarios, you get the same effect -- stretchy initially, and yet very stout when severely loaded.