Haven't used the Kanger OCC coils in a while since I find it easier and less problems using the Aspire "Replacement" BVC's in the Subtank mini. I save the casings.
I do rebuild those BVC's by having hubby drill out two holes (opposite each other) with a 5/64 drill bit. Also have him step drill out the top so the metal "lip" is gone and smooth. The BVC's I rebuild are the old ones with the small holes. Using the 30 gauge Kanthal, I space the coil to 1.5 to 1.8 ohms (7 wraps), insert coil from top, capture through drilled holes with heavy duty pin, finish off with insulator and pin insert. Take out heavy duty pin and wick through those drilled holes with cellu cotton (rayon) leaving 3/8" fluffy bunny tails on either side.
I'm very much a Tootler and don't go much higher than 9-10 watts or 3.8-4 volts, so the above "modding" suits me as well as using a rebuilt Protank 2 coil. The modded Aspire Replacement BVC can also be used the Subtank nano and the Toptank.
I chain vape and go through around 15 ml per day, so I dry burn and clean with those tiny round GUM dental brushes for between your teeth about every other day. Rewick and start afresh. Takes about 5 minutes. Do a recoil session of 6 casings every month. Takes an hour.....I'm old, shaky and half blind.
I haven't broken into my second 5 pack of coils yet. It's been a year.