@Jack Barnes as for the tack if you don't have a bowsprit you could you this setup http://www.atninc.com/atn-tacker-sailing-equipment.shtml when I fly our spinnaker I only use (1) sheet, not to say that you couldn't use (2), the issue being in order to tack when flying a asymmetrical you would have to douse it and redeploy on other side. Which is why a top down furling system or a sock is usually used in conjunction with the spinnaker. A bowsprit allows the sail to get out front of the bow pulpit and improves sail shape.
Mark
Mark