Hey Viking, we used to make them out of old alveys with strong braid and old broken stiff butts off rods with guides still on and used a propper 5kg lead down rigger ball, mainly used to catch mackies and trout, rankins. For Sailfish we didnt down rig but just skipped a couple of garfish close behind a bird teaser and freespooled them into their gobs on point of contact, never really had any bird problems. You only need your gear 10 or so metres behind the boat. 

Leave your bait sitting in an esky on the deck...let the teasers do their work to bring the sailys to you. Much better to drop the bait into an open mouth as the fish turns away from the boat. Trying to hookup on a downrigged bait with a Saily, will be frustrating I think, with low % hook ups I think and Mackie hits etc. And you miss the visual aspect as well. Your teaster can contain a large hookless bait such as Milky or Tarpon or mullet etc that the Sails can get a good feel of before you switch it for your baited rig. Anyway just my suggestion.