Steve -- Half an inch is far enough on the Eclipse. That will bump you up right against the needle seal. You don't really need to scrub inside the seal. Pulling the needle gives it a good wipe.
There are different opinions on how to pull a needle. Pulling it out the front supposedly prevents paint from being drawn into the rear of the airbrush. But, my experience is that if you give the openings in the cup a good flush with an eyedropper before removal, there will be only a slight smear of paint on the needle, not enough to cause a problem. I always pull the needle out the rear. Some airbrush needles have identifying grooves in the back end. I don't like dragging these through the needle seal. Your Eclipse doesn't have these grooves, so pull it any way you feel comfortable with.
Back flushing with a cup full of paint probably does force a little into the needle channel. Back flushing while cleaning probably rinses some of it out. I don't back flush. I mix paint before pouring it in the cup, and I think flushing with an eyedropper does a better job of cleaning.
If you still get a little drag when you remove or install the needle and you're not getting leakage into the rear of the airbrush, your needle seal is OK.
Don