L -
At 20 yards, without bare shafting the odds are you won't be able to tell the difference between an appropriate Dacron and most of the newer materials.
However, 16 strands of Dacron is for bows in excess of 60#, doubt your bow is that heavy, so yes, because of that there will be a performance loss and you might have nock fit problems. As far as Dacron creeping (not stretching, look it up) every session, ah, no. Once settled, after about one session, it will be as stable as anything out there.
And yes, even if machine made, every string will be slightly different, so a quick check is in order.
Viper1 out.