Hello and welcome to VU
I feel your pain. I had nothing but problems with stock Kanger dual coils. I couldn't run them over 4 volts and it seemed like I had to let them sit overnight before I could use them and even at 4 volts with a 1.2 ohm coil it would constantly dry hit and burn out. One thing you can do to help is poke a needle at the openings where the juice flows in to help the coil feed faster. Another thing you can do is dry burn and clean your coil heads. There are youtube video's on this if you search for them and it's much easier to show in a video than writing a paragraph or two to explain.
I feel like since Kanger mass produces so many coils that the quality is hit and miss these days on their little dual coil heads. One pack might be good and each coil lasts a week or two and another 5 pack every coil is bad and you're lucky if each one lasts a day and you feel cheated and it sucks. I feel your pain believe me. If the new subtank OCC heads weren't such an improvement over their dual coil line I would have sworn off Kanger all together. My very first good vape setup (after the yucky Blu ecig I hated) was a Kanger T2 and after the Protank 2 and mini were so good, the Aerotank and Geni tank coils felt kinda like a big let down
Another thing you can do is get some wick and wire and rebuild your heads. They will last longer and give you a better flavor and you can decide if you want to rebuild them as a single or dual coil head and what kind of wick you want to use. Although I mainly use cotton in my Kayfun's and RDA's I prefer to use Ready X Wick in my protank, aerotank, and evod coilheads. The stuff lasts forever because of how easy it is to clean and dry burn. One foot of Ready X will easily build a dozen or more heads and will last a good while. I originally used ekowool for this but after trying the X wick I have to agree its better. The advantage of using X wick or ekowool is that it is hollow. You can take an 18 gauge needle and slide it threw the center of the wick making it solid so you can easily wrap your coil directly onto the wick as apposed to wrapping it on something like a drill bit and then trying to feed the wick threw. By wrapping the coil directly on the wick you will insure a proper fit for better wicking and when you're done you just slide the needle out, install your coil into the chamber and put it back together and you're good to go with a perfect fitting coil.
I hope this helps a little, you don't have to rebuild but many of us used Kanger heads as our first step into the rebuilding world and most of us found out that we liked it and now vaping is more than just a lifestyle choice but find rebuilding as a fun hobby. I wish you the best of luck and happier vaping