Either way works. I have seen people put a washer on the cable and then the spring followed by another washer. Makes the cable stay put. Or you could do like you said and use a spring hooked to the pump and then the cable ball.
So FX, you have a Kawie 650 0r 750 pump in you FX1? That is sweet!
Jawbreaker, The stock X2 trim cable works just like a stock steering cable. They push in one direction and pull in the other.
So for example, it pushes that cable ball up to trim the nozzle down and pulls the cable ball down to trim the nozzle up.
The trim set up Kawaboy is making will use a pull system where the cable pulls on the cable ball. So he may need to swap the trim ring over to make the pull, throw the nozzle the right way he wants it, I am guess up since he is a freestyler.
Kawaboy, go to a bike shop. You can get this brake bolt/nut setup. It has a bolt through the bolt for the brake cable. Then you tighten the nut down to hold the cable in place. I would go with a larger cable diameter like FX said to reduce stretching.
DBR