cantabile MaH is nothing to do with the coil, its simply to do with battery life. The bigger the number the longer the battery will last. It has no bearing on anything else at all to do with the device :)
ohms is how the coils resistence is measured. So the lower the number of ohms, the less power you need to get a decent vape. The higher the number, the more power you need.
Where you have to be careful with ohms is if you're using a variable voltage battery, and you have a low resistence coil (say, 1.8 ohms) you risk just burning it straight out if you turn it up too high (I have done this).
With a higher resistence coil if youre using a fixed voltage battery (A normal standard battery) you run the risk of it basically not being able to pwoer it at all so no vape.
I find with my standard batteries 2.4 - 2,8 ohm coils work fine. 1.8 i have burned out pretty quickly on a normal battery, and ive not burned any out quickly on my ariable voltage batteries either.
A standard battery puts out about 3.7 volts.
Here is a chart that gives you the best voltages for different resistence coils (very good if youre using a variable voltage battery)
thevaperstable.com/wp-content/uploads/Safe-Vaping-Power-Chart1.jpg
You can see how the lower resistence coils run the risk of burning out sooner etc :) I found it very helpful, hope you do too.