If you think of the three modes your tank has to work through: normal use, laying on its side and refilling your choices of wicking become important.
IMHO: having your wick stop at the top of the juice channels might work well for some but I tend to always get leaks when the mod/tank is laying on its side or I'm refilling (even using technique to be described below). Closing off the juice flow will slow down the leaking on the side and refilling modes.
The issue with having to much wick (and in the channels) is that you'll notice your coils are starving for juice. You'll get a few good hits as you vape off your primer but then the vape will start to be lame. IMHO: you need to have wick in the channels but not "packed in" tight where it strangles juice flow to your coils.
While I use rope, I always stuff the ends into the juice channels and then cut it off at 45D in the juice channel openings. I like enough wick to fill the hole but not so much where it is packed in. Once I prime it I'll use tweezers to push on the wick from the bottom of the juice channels to slightly push the wick up to make sure that they are freely "floating" in the channels.
Refills were my #1 leak starter. However with juice and airflow turned off, I can open the top, fill to the top of the glass, recap and then INVERT the tank so the air bubble is where the juice control ring is and then open the air and juice flow before quickly righting the tank (top up). I get little if any leaks if I do it that way.
YMMV.