My boat came with a symmetrical spinnaker, and I purchased a sock (V.F. Shaw Chutescoop) for it, as well as an ATN Tacker. The Tacker is a plastic collar that fits around the headstay, and it allows the spinnaker (symmetric or asymmetric) to be flown without a pole (the tack is attached to the Tacker rather than the pole, its just as though the pole were forward against the headstay). It allows the tack of a symmetric spinnaker to be flown at pole height (as designed) without the sail rotating to leeward as it would if a tack line were led to the anchor roller.
Practical Sailor reviewed the ATN Tacker in its August 1, 1996 issue. The article says you can fly the spinnaker from 80-160 degrees true. I''ve found that to be approximately correct, perhaps a bit optimistic on each end of the range. Inasmuch as cruisers typically only use spinnakers in relatively light air, where tacking downwind is faster, the inability to sail dead downwind isn''t much of a problem.
The lines needed with this setup are halyard, tack line, and sheet.
With a regular pole you need a guy, spinnaker pole topping lift, and spinnaker pole foreguy, but no tack line. If you want to be able to gybe on a larger boat you''ll need two more lines: a lazy guy and a lazy sheet. It''s a lot of work to get it all hooked up and manage it.
If a sock is used there is another line (typically one continuous line for up and down). I recommend leading the line aft and having some sort of quick cleating arrangement. One doesn''t want to be on the foredeck of an out of control boat trying to douse the spinnaker. You need to be able to pull it down without worrying about a gust catching it and causing the sock to ride up again. Take a look at the spirt J boats. They have a couple of cam cleats on the side of the cabin house for the sock controls.