Juice is always Burning before the tank is empty

Suggest getting a Joye eGo-c. They are regulated to 3.3-3.4 volts. If you have a T3 and use the 2.2 or 2.4Ω coil (T3 coils run 0.1 to 0.2+ ohms higher than marked), you shouldn't be getting any burnt ejuice, unless the ejuice is very dark and has particulates that cling to the coil.

Another 'volume fix' would be to get the Baby T3 (sun vapors) where the ejuice isn't as 'exposed' to the coil for a longer time than the regular T3. Still shouldn't vape it dry but you can go longer than a 1/2 a tank. Also with the bottom coils, vaping with the PV pointed down would help keep both wick ends in the ejuice.

 

Could very well be the juice. A buddy of mine has a particular juice that no matter how he puffs, what voltage he sets, what clearo, carto, RBA, whatever he uses, the juice gets dark and starts tasting funny. Try a different flavor, or if this is all from the same place, try a different manufacturer.

If airflow really is the problem, then the iClear definitely is not the way to go, too tight a draw. You'll want an atomizer with a particularly airy draw to get more airflow to the coil with less "sucking." But I really doubt that's the problem.

Also, have you tried rinsing, dry burning, and priming the heads before use? I've found this can help get any "manufacturing residues" off of the wick and coil, which will improve flavor and prolong head life, and the priming of the coil/wick will help deter any initial burning from the first few puffs. In my experience, silica really is not the best at wicking, and if you fill a dry tank with a fresh coil/wick, you really need to let it set a bit before taking your first drag to let the wick not only get wet, but let the wick get really saturated at the coil. Dripping a few drops of juice directly on the coil and the base of each wick (where it enters the center of the head) will decrease the initial soak time and improve the first draw.