I have to question what I often read as folks using silicone fuel tubing to seal the needles. I don't see how silicon can seal a thread as it can't reach down to the minor diameter.

This leaves much the same air path there was before one added the tubing. I suspect that what is really happening is that the tubing is dampening the needle's vibration and limiting the side to side movement that causes the flow disruptions (leaning out) of a false needle. If the needle does't vibrate in the jet and change its position the fuel flow won't change giving the impression that there is an air leak (lean) It looks to me that the silicone tubing does help, it is just that the mechanism has been wrongly identified.