My Kanger subtanks don't like max vg. Especially the way I vape. Chain vaping is something I love doing.
If you are using the premade coils(or rebuilding the OCC heads), here is something for you to try:
1. Remove the coil
2. take a pin/needle and just slowly work it all the way through the coil.
3. When the tip pops out the other side, pretend you are using it like a little bitty hand crank on the blunt end of the pin.
4. remove pin
5. look through coil and see if you can see a clear hole straight through coil
6. If the hole is not visible, repeat steps 2 through 5 until it is
7. Re-prime, reinstall, wait a few minutes, and then start vaping.
I used to have trouble with the coils on my subtank mini not being able to wick my juice quick enough when i was chain vaping. I did that method above, and now I am able to run juice that I know is 90% VG with no issues at all. Can't guarantee it will work for you, but it has worked on every one of the OCC heads I have used. If you do it right, you should actually see little air bubbles pop out of the sides of the wick occasionally after vaping(or possibly after every hit). If you are seeing the air bubbles, that indicates that the wick is being fully saturated.