Those folks were visiting us in Houston from Louisiana and Arlington,TX. Some of them use the socks, but we don't use them. I considered it back when I was starting to use the chute, but decided I liked the "basket method" better. (I use a laundry basket instead of a bag but it's essentially the same as what you do now).
Nevertheless, here's what I know about socks, based on discussions I've had and my observations.
The front of the sock is somehow tied to the foredeck, on one side or other of the forestay - usually the port side. The back is likewise secured on the cuddy or the deck just outboard of the cuddy. The "mouth" of the sock has to have some sort of rigid opening at the front of the sock to hold its open so that the spinnaker will move in and out of the sock fairly.
Most socks I've seen involve some sort of a metal or plastic ring sewn inside the mouth of the sock. The shape of the ring is either round or "D" shaped. The best one I saw was a fiberglass device shaped like a trumpet horn. It was homemade as I recall.
The spinnaker itself must have a trip line attached to it at the middle of the sail. That point in the sail must be reenforced and have a grommet to attach the trip line. So you'll need to have the sail altered by a sailmaker, unless you're handy with the right tools for the job. The trip line runs from the spinnaker through the mouth of the sock and out the back end of the sock. To launch the spinnaker, the halyard and guy are hauled, and the spinnaker comes out the tube and up. When the spinnaker is doused, the trip line is hauled and the halyard and guy are eased, pulling the sail back into the sock. While many people have had success with it, and it can be a very fast way to launch and douse that sail, I prefer to use the basket method, because it's simpler and it's easier on the sail. The spinnakers I've seen that have been launched and retrieved using the sock seem to wear more quickly than those launched from baskets.
You might consider your technique. It's hard to visualize the problem you're having and I've never encountered the situation you describe. We've found that on a douse, if my crew pulls the clews of the spinnaker together just before I slowly ease the halyard and lower it into the basket while my crew stuffs it into the basket that it doesn't get caught on anything. We make sure we give ourselves have enough time to get the sail down well before we round the mark, and with practice we've gotten faster, so that we have come to a level of expertise where the spinnaker will be in the basket and the pole stowed just as we go closehauled.
I've also made sure I've got proper rigging tape on the spreaders, the forestay turnbuckle, and any place between the basket and the halyard sheave on the mast where it looks like the spinnaker could get snagged on anything.
I've had the spinnaker snag going up. The worst case was getting the sail dragged between the shroud and the boom, if I were ease the boom too fast after rounding the windward mark. I made a small tear in the sail and had to take it in for repair.
Good luck, I hope you find a method that works for you.