My build:
After three tankfulls, cotton is dark, but not burnt... Taste on the last tank was same as the first, more or less. The coil is close to being gunked, but still usable.

Coil is 28g, wrapped on a 2mm allen key. Smaller gunks faster - one tank only. Larger, haven't tried and won't, this build is perfect for me. Ohms out to 1.1. Something like 8 wraps? I play it by eye.

Second pic is burning the coil... It's still fine, not going to replace it yet.

Third is the base with the airflow control removed - the green bit there is a C-shaped o-ring section to stop wobble / shorting.

Fourth is initial cotton packing. This is cotton from CVS cotton balls... Not boiled. I'm not going minimal quantities here - it's fairly tightly packed. I keep the top of the cotton packing below the top of the coil by a smidge. Again: there's more cotton in there then most guides would suggest. Less cotton would make it flood, in this build. Also note, nothing's extending out the wick holes - it's all in the central area.

Fifth, wetted the cotton with juice. Saturated fully... I also use this time to tamp down the cotton around the coil, keeping one wrap fully above the level of the cotton. Not doing this results (in my experience) in the build gunking up / restricting airflow.