I use Kanger OCC coils, too. The older (2015-16) box shaped ones and the newer (2016-2017) cylindrical stainless. I mix most of my own juice too, and even the few commercial juices I don't clone have 30 PG max.
Even though the Subox device is 50 Watt capable and Kanger claims the range of the OCC line of coils is up to 50 Watts, they are assuredly not 50 Watt coils. The only one in the OCC line that might be is the Clapton, and that's because of the slower heat up time.
Max VG on a non-Clapton OCC coil near 50 Watts is going to disappoint. You might try the distilled water route, or trying to puncture the cotton at the wicking holes with a pin or needle. The Subtank Mini C tank that comes with the kit is a good flavor tank, and at least for me, the Subtank/Toptank/Mini C sweet spot is 35-40 Watts.
No water addition here, and the pins and needles stay in the gentleman's sewing kit.