here is a simple layout for jib shees from AUS 9 (thanks Ed for the pic).
As you can see, sheets go through tracked pulleys on the foredeck-down to a pulley/fairlead to a cleat-then across to the opposite seat end to a piece of elastic. The elastic runs throught the seat to connect to the other sheet.
This keeps the jib sheets near the end of the plank so you can grab them for tacking/gybing/adjusting.
Don't make the sheets to short or you won't be able to get your carriage aft and still adjust the sheets. And to long and everything will foul in a lovely mess in the middle of the boat.
On the foredeck tracks:
Have elastic to pull the pulley/car outboard when going down wind
To pull the pulley/cars inboard, set up a line that runs o the opposite side of the boat (so the leeward car can be pulled in on that tack). A good idea is make this line continuous so no matter where you are in the boat, when you pull it both cars come in to their windward position.
Hope this helps