I have a one line system. 5mm robline run per http://www.catsailor.com/bb files/113750-spintang.gif
I hope that gets you there. There is a great write up on the forum with pics that I used, I'll try to find it.
I ran the retreval as described previously but found that the spin wouldent go all the way into the bag and sometimes balled up at the hoop. I tied a 12" line to the tack so that it would go deeper into the sock. I also put a tenis ball on the line about 12" from the the upper attachment point on the sail.
I attached a bungee across the rear of the tramp and attached a small block which the sheet - retreval runs through to take up some slack. Didnt need a grommet in the tramp as the sock is far enough forward for direct pull out the rear.