Originally Posted by grizz1

+1 - the fuel tubing works a treat.

As Magpie said, cut the tubing a little wider than the O ring groove and fit the tubing into the O ring groove with the excess tubing facing the top of the needle assembly (ie the adjusting end not the needle tip).
Now gently screw the needle into place. The excess tubing will be cut away by the needle housing and will shred out the top as you screw the needle home. Back the needle out a little to remove the shredded excess tubing and you are racing.
The fuel tubing will last for yonks, and provides a nice tension on the needles which is easy to adjust but will hold itīs position.
Give it a try and see if it works for you