I'd agree with JRP given the size of your boat. A symm spinnaker on a 28 footer should be totally manageable without a sock (which adds expense, weight, and complexity - esp when/if they get fouled)
We sail a 35 footer now, but as a frac rig the headsails are the size of an average 30 footer.
For a easy, unloaded takedown this is our standard procedure:
Sail fairly square downwind
Ease (gently) the pole to the forestay
Grab sheet as far up as you can (under the boom, standing in the companionway)
Release the guy completely
Pull the sheet til you have the clew in hand
Gather in the entire foot so both clews are in hand. By now the sail should be completely in the lee of the mainsail and quite relaxed.
Ease the halyard as the spinnaker is gathered -almost in a tube itself, pulled in under the boom and stuffed below.
Don't forget to secure the sheets/guys on deck before starting the engine (don't ask!)
In really light air you can try to put it directly into its turtle bag - in that case from the foredeck grab mid foot, gather the clews and have someone ease the halyard as you gather cloth and stuff in the bag, leaving the three corners accessible on top.
It's a rewarding sail that can make an otherwise boring day more interesting. Choose your times (not too much wind, but not too little either - that's just frustrating). Enjoy!