Something I think doesn’t get considered in wadding use (especially with blankets) is protecting the shock cord.
parachutes are mostly either plastic or nylon. neither tolerates ejection charges well,
shroud lines are often cotton thread (I have heard some also use various fishing lines). These also are not heat tolerant,
low power shock cord are usually made of either elastic or Kevlar. Elastic is poorly tolerant of heat. Kevlar does much better, but is NOT BURN PROOF.
shock cord protection has at least two techniques. One is a forward mounting, often just below the level of the inserted nose cone shoulder, think classic Estes tri-fold. Even WITH this, when PACKING may bring this cord close to the forward end of the motor mount without wadding. (What I don‘t like about the tri-fold is that it breaks up the smooth forward inner surface of the tube and can hang up your chute.) I like attachments near the motor mount, but it puts the first few inches near the hottest part of the ejection blast. You can use
@hcmbanjo ‘s replaceable technique for non-minimum diameter rockets which gives you a chance to inspect or replace. For minimum diameter I have had a number of rear mounted shock cords burn through after a number of flights.
second option with motor mount attachment is either heat shrink tubing around it, some other protection, or a wire leader. Wire leaders are kind of awkward