As long as they're authentic kanger stuff then you should be good to go buying from most places. Now there's a couple directions we can go here. MVS sells them in the 0.8ohm range here.
Kanger Dual Coil replacement coil 0.8ohm
Sub ohms can usually handle more wattage... but I'm too tired to math, so ....ed if I know what will happen if you put two in the same system... maybe turn into .4ohm? That's probably wrong though lol.
You can get regular ones in either 1.8 or 1.5 here
Atomizer Head for Aerotank Mini, Aerotank Mega
But the ones that I really want to try myself are their new VOCC ones. Works in all the kanger dual coil systems (and your double-dual monstrosity lol) but use a vertical coil design with organic cotton similar to what you'd find in a nautilus. And having rebuilt some of the dual coils with organic cotton, I can testify that these will improve flavor.
They're here.
Kanger VOCC Dual Coil Denver
Note:
MVS is pretty well known. But I've never ordered from them. And I've never heard of vapor leaf, but they we're on the first page on the bing search lol. So as always, buyer beware when taking advice online. And remember
battery safety. Always make sure your battery can handle the ohms of your coils before using.