Those of you that are having burning issues with the 1.6ohm Z-Coils, I have an outstanding solution that does work.
Open a new coil pack and grab a sharp-tipped syringe needle, think mine is a 21 gauge (green).
A blunt tip will not work.
Grab a new coil and poke the needle through one hole slowly until it exits the opposite hole. Now grab the base of the needle and slowly move it around in a circle motion. Do this until you feel the cotton loosen up a bit. Do the same thing in all 4 holes so that when you're done you should have 2 puncture holes in each.
Grab a bamboo toothpick and cut off the sharp tip. You're gonna use this to compress the coil and hopefully get rid of any big gaps or hot spots. GENTLY insert it into the top of the coil head opening and slowly slide the stick up and down until it feels loose.
Use the opposite end of the pick to align your post air hole on the bottom of the coil. You want good airflow so make sure that you don't forget this step and line up that hole with the two open slots.
Juice up the head until its VERY saturated and insert into your tank.
After about 2 or 3 tanks, repeat the above steps with the syringe and just make sure that the cotton stays loose and the coil stays tight.
I use 90% VG, 10% PG ... and I get about 10 full tanks before I start getting the burnt-... flavor.
You can get another few tanks by using the bamboo toothpick to clean the coil. Yes, you will get black goo on it, just wipe it off the toothpick with each insertion until there nothing else being deposited on it. Insert coil into the tank and fill your tank 1/5th full of PG only, drop 4-5 drops down your drip tip, open your air flow valve all the way, tip the tank upside down (with coil inside) and start blowing through the wide open airflow valve so that the remaining black goo drains out of your drip tip. Wash drip tip with water when finished cleaning.
If you do this correctly, you should get at least 3-5 more tanks out of the coil or as much as 10 more depending upon how often you clean it this way.
I've yet to find a good way to rebuilding these but I do know that it can be done. Tearing them apart is pretty easy though (press-fit), it's using the right amount of Muji cotton that's difficult.
Lastly, I'm using an old black
Eleaf TC60W at 15.7W, this is the sweet-spot for me.