I just skimmed the 10 pages so sorry if I'm repeating but a few small pointers.
Gurgling after you just refilled the tank MIGHT be because when you are putting the top back on, the pressure is pushing a little bit of juice through to the deck. You can rectify it by covering the mouthpiece with a tissue and giving it a few sharp flicks to flick the juice out. To prevent it, put the top cap in place just enough to form a seal, turn the tank upside down so there is an air bubble at the 'bottom' of the tank and then tighten it into place. And don't overfill your tank, leave a small air pocket in it.
Flavour suddenly disappearing after a rebuild can mean that your coil isn't aligned within the airflow. Check that coil is close to the airflow, you might need to move it a tiny fraction higher or lower. Try to imagine how the air moves through the tank and whack that coil right in its path!
You don't need to change the coil every single time you change the wick, pull out the wick, turn down the watts, give it a gentle glow so the crud crisps up, and I recommend a tiny wire brush to wipe off the crud.
I find with this tank it doesn't wick nicely if the tails of your cotton touch the deck beneath the rings, so precision wicking required for this little bugger!