While you waiting for new O rings, just make some out of fuel tubing. I have been running the fuel tubing O rings for a year now (because of the crumbling brown factory ones) and they work fantastic.
Just cut a slice of fuel tubing a fraction wider then the groove in the needle. Fit the tubing over the end (with a pair of long nose pliers and slip it into the groove. Sit it so the front end (needle point end) is in the groove and the other is sitting proud of the groove. Now gently screw the needle in until the tubing is completely out of sight. You will notice the excess tubing from the rear of the needle peel off as it is forced into the needle seat or tube. Now screw the needle back out and you will see you have a perfectly fitting fuel tubing O ring. The tubing is fuel resistant, slippery enough to allow easy adjustment but still hold the needles in place, won't dry and flake and is soft enough to keep a perfect air tight seal. Easy and very cheap
Hope this solves your problem and gets you racing