Agree with those who have found keeping it simple ends up working. A good ego type battery, 900 mah on up and LR cartos. There is no better spare tire in the vaping world. No matter what they do, a string going thru a coil can only be so good. Everything that comes out with this concept, addresses everything but. Before long, you will find the consistent better quality of the flavor, clouds of vapor, and draw, to end up winning out over things like excessive throat hit and such, and cheap enough to toss when it stops working. I have fiddled with tanks for a long time, and even though I can mod just about anything to work better than delivered, I know that each puff is on borrowed time before it has issues, even if only temporary.
Tanks and such are really a novelty. Reverse their roles. Find good cartos (LR dual coils if you like warmth, LR singles if not) that you like with a good strong battery (1100-1300mah) for the brunt of your vaping and just use the tanks when you feel like experimenting or fiddling. Lower voltages like the EGO types usually won't burn a carto if it is 'wet' and the juice is a quality mix. It's easier to top off a carto with 10 or 15 drops at a time than it is fiddling with most tanks. You will also find that your juice lasts longer just from avoiding the flooding issues or burning off juice with primer puffs, or the amount it may take to get some of these finicky tank systems primed.
In spite of what many people say about cartos tasting like filler, half of it is that they bring out much of the actual flavor of what's in the juice, even that which may not be favorable, that would otherwise be muted out in a string setup. Sometimes I vape unflavored juice. It's VG nicotine base, VG no nic and distilled water. In a carto it tastes pretty much like nothing other than a touch of sweetness from the VG. If there was an adverse flavor from the filler and the fabric wicking, it would really show when vaping flavorless.
I am a reborn carto fan. Specifically the Resurrectors. Wasn't always so. I started with them and had condemned them after only trying 2.5-3 ohm on 808's. Went right from those to a provari and a lavatube and just about every tank that has come out since. All that stuff is now in a box. I now have 2, 1100mah (not VV) KGO's and a joytech 18650 EGO. I have not been without a quality vape since. These are now considered entry level devices, but anyone who has been doing this for awhile will come to the realization that a good strong, long life battery, with a reliable button and a device with a nearly perfectly fed coil wins.
The good thing it usually passes if we're patient and all is good again. Shopping for some new toys makes us feel better too sometimes 
