I have made these real fast spinnaker sheets:
It is 10 mm double braided polyester spliced to 4 mm dyneema. It is very light at the flying end and runs easier in the blocks.
I like to have a thick end in my hand. It is very comfortable. The thin end makes the spinnaker fly in very light air. These spinnaker sheet I can use in every wind. By splicing the two yourself, you can choose exactly the lines you like.
I also made new barberhaulers by spicing 3 mm dyneema to a very light ring:
At the aft end of the barberhauler I have spliced on a 5 mm polyester cover, the outer part from another line:
This weighs 1/3 of my old barberhauler of 5 mm with a block at the end.
I now have the fastest spinnaker sheets of Öresound.