With KGD (or any cotton) I've found that tighter is better for flavor. I've always made cotton wicks that will slip and slide back and forth
through the coil easily. I assumed that the
juice would swell it once it was wetted.
For a while now, I've been making KGD wicks that I have to twist really tight on the end to enter the coil. I have to twist the wick and pull it to make it slide through the coil. I get a little bunch up on either side of the coil when it's in place. If I do that, there's a boost in flavor that I never got from smaller wicking.
I always avoided a tight wick thinking it would starve from the pressure at the coil. Not so. My wicks these days would bend the coil legs if I didn't twist and pull at the same time to make it move through the coil.