These guys certainly handed you the best tools one can ask for.
To be more specific.
Best flavor in a tank would be 801 Fusion, however I would go with the 510 Fusion as it's more optimized for tank use with a thinner batting density and lower batting setting. Makes refilling a breeze.
Best results on an ego and a Twist would be a 1.8 atomizer or LR cartomizer. Our LR cartos are only rated at 2.0Ω. None of our coils hotrod and will not demand such a high current from the powersource. Even though we use different coils in our products, they are all built for that smooth analog simulation, just with better flavor and vapor production. If you use 3.0Ω on your Twist, you will just be spending allot of voltage and lowering your run time drastically.
Actually Iken, it's not higher voltage that decreases your runtime, it's higher current (or amps). I'm not sure what the current rating for an ego twist is, but I'm guessing its somewhere around 2.6amps...so:
3.9v setting for a 1.5ohm carto gives you 10.27w at a current of 2.62amps.
4.5v setting for a 2.0ohm carto gives you 10.27w at a current of 2.27amps.
Using a 3.0ohm carto will max the ego at 4.8v output with 1.6amps of current (this is the best battery life), but it will only generate 7.68w, which is generally considered a fairly cool and week vape.
Using a 2.0ohm carto on ego style batts generally provides max performance without sacrificing battery.
Anything greater than a 2.5ohm carto on an ego, is usually not worth it as the vape doesn't get enough heat.
Using a carto under 2.0ohm reduces ego performance because its limited to the low rates current, at maximum current draw on the battery.