There are a few different references to heat in your questions. I'm not an electrician or an engineer, so I'll try to explain it to you the best I can.
I found this on reddit and I think it explains coils and heat way better than I can:
"Simply put, resistance refers to the coils resistance to electrical flow. Remember, a coils job is to be a path for electricity, the heat is just a byproduct of the electricity passing through it when there is too much electrical flow for the coil to handle. Resistance measures how much electricity can be flowing through a coil before the coil begins to “resist” the flow of electricity and begin producing heat. Using that logic, lower resistance, meaning less resistant, means it allows for greater flow of electricity and vice versa. Here’s a deeper explanation:
If a coil has HIGH resistance, then it is not very open to electrical flow, i.e. the coil resists the electricity, and even a little electricity flowing through the coil will cause friction and therefore build heat. Because it is very resistant, not much electricity is required to build heat, so low wattages will build heat quickly.
If a coil has LOW resistance, that means it can take a large amount of electrical flow without building friction and creating heat, because it is not resisting the flow of electricity. This means the electricity is flowing smoothly without creating heat, because the coil is not resisting it. So the LOW resistance coil requires more electricity to build up heat, meaning you have to use higher wattages."
MTL coils are usually made with higher gauges (smaller circumference) and heat up quicker with less power. A 32 gauge wire wrapped 5 time with an inner diameter of 3mm is going to give a higher resistance value than a 24 gauge wire of the same material wrapped 5 times with the same 3mm inner diameter. Because a 32 gauge wire is thinner, it will naturally heat and cool faster than a 24 gauge wire.
The Zeus X is a DL atomizer meant for dual coils. There's a lot of airflow, so you want a lot of surface area vaporization, otherwise you're going to get muted flavor. I'm not sure what kind of coils you used in the Zeus X, but if you don't find a good balance of chamber size vs. surface area vaporization, airflow, and wicking, any number of issues can arise due to poor airflow circulation, or not enough vapor production. Coil positioning in relation to the airflow can easily be missed, too much cotton restricting smooth airflow and wicking is a common mistake, etc.
Dual coil atomizers will always have a tendency to heat up your atomizer faster and hotter than a single coil, and will therefore need more time to cool off between puff sessions. You also have to keep in mind that you've added another coil, so you're going to need more power and there's going to be a longer ramp up time for your coils to reach vape temps.
