There is a balancing of forces going on. Capillary action occurs due to surface tension. Basically, the juice trys to soak the wick so that the surface area of liquid is minimised. In a genny, gravity acts towards preventing/slowing this.
Another thing that can slow or stop this capillary action is the pressure (actually, it is a lowering of it) inside your tank. As you vape and draw up liquid, you reduce the contents of your tank. This means there is less pressure inside your tank than the air pressure outside of your tank. Juice can be prevented from wicking due to this imbalance. A way of preventing this "pressure locking" of your tank is to make sure the cotton isn't blocking the wicking hole too much (so little bubbles of air can get in). This is where trial and error comes in: too much cotton = pressure locked tank, but too little cotton = leaky tank.
EDIT: it looks like the sxn corolla might have tiny holes drilled into the deck (for filling and to prevent this pressure locking from happening). I can't be sure though.
I vape with mesh, and I always make my mesh coil at least 0.5mm thinner in diameter than the wick hole. This works a treat. Unfortunately I can't give you exact pointers for this tank, particularly when using cotton. All I can say is try experimenting with the thickness of cotton.