The recomendation for carto tanks is because this eliminates the too dry, too wet carto syndrome
I love my carto tank setup.
On an eGo twist, I use 1.5 ohm cartos and get ridiculous amounts of vapor. Especially with Goodejuice house Blend menthol Tobacco.
Smoktek single coil cartos work nicely. Out of 5 or 6 cartos I've only had one that was subpar. Maybe I filled it wrong.
There is a trick to filling the carto in a tank. On the first fill, put a tiny amount of juice on the outside of the carto and slide it into the tank.
Stick a round toothpick carefully in the top hole about a half inch. The goal is to plug the Center hole so juice doesn't get inside. Drip juice in it, 2 or 4 drops at a time. Then wait. (sometimes in shake the carto gently to help the juice settle.) then drip 2 or 4 more drops. Do this about 10 times.
Then, fill the tank, by sliding the carto down in the tank until you can squirt the juice down the side of the tank. Take out the toothpick.
Once it's full enough, let it rest for a few minutes. I take some puffs on it without engaging the battery.
The goal in all this is to fill the tank and get the inner batting of the carto moist. If the top looks very dry, add a few more drops with the tooth pick in place.
It sounds like more of a process than it is. You can find plenty of videos on YouTube on how to fill a tank. Just Google "how to fill a DCT tank". While there are various methods, they all work. The keys are, make sure you do not get juice in the inner hole of the carto (hence the round toothpick).
You will get wonderful vapes and no dry hits. Refilling the tank is very easy. Just slide the carto down enough to get juice in the side and then push the carto backup.
There are tank filling tools available to speed this up. I bought a 4$ one from Phiniac that's worth its weight in gold.
Use single coil tank replacement cartos. For ego batteries, use 1.5 - 2 ohm cartos for the most vapor quantity.
If you want to go this route, I'll be happy to make specific product recommendations. Just let me know and let me know what vendors you prefer.
Typed on my mobile. Please excuse typos.