My first one had loose needles also. But my latest one is tight. I believe they updated the carb o-rings with a slightly larger one so they stay where you set them much better. You can also put a dab of o-ring grease on all 3 needle o-rings before running it so they don't rip/tear or dry out as fast from the heat. Just like with exhaust gaskets, they should be replaced every once in a while too.

I know OS and Go engine carb high speed needle o-rings will fit too if you are in a pinch at a race. I used an old OS o-ring while at a race when my needle moved and then I replaced it with a new Go o-ring when I got home. But in my newest Arrow GTR I am using the stock o-rings. When I have time I'll pull them out and see if they are larger then before.

Part # for the complete Arrow Engine O-ring kit (11 gaskets & o-rings) is
A-ST-014