As some of us Katana owners I had been having some wicking problems with my Katana, tried a lot of different mesh setups and advices, sometimes the katana worked good for some days, but most of the time there were dry hits. I didn't want to modify my katana (opening the filling hole for example), last night I was playing with it and thinking why the dry hits, I came to the conclusion that dry hits is due the mesh is not in contact with the liquid, for example Katana with half tank filled, when you vape it at 90° the mesh is not in contact with liquid.
I would like to introduce you my
®patented© method to avoid dry hits (standard setup with screw in the filling hole)

:
You will need:
* Plastic tube approximately 1.7 cm long, 0.5 cm outside diameter. You can find that plastic tube on the spray cans (I took it from a empty deodorant can, be careful when opening compressed content cans).
* Scissors or cutter.
* Know how to disassemble the top cap.
Some pictures:
Standard setup (filling hole screw installed):
You can see how the liquid goes inside the wicking tube© when Katana standing up:
When you vape it the liquid enters inside the wicking tube©, allowing better wicking:
The plastic tube I took from a empty deodorant can (wash it very good and boil it):
Cut a 1.7cm plastic tube piece and make some cuts on one end (this end will be at the tank bottom) to allow the liquid to enter inside the wicking tube©:
Install the plastic tube inside the Katana tank, where the wick hole is placed, like in the third picture.
Install the Katana top cap, the +/- posts will help so the wicking tube stays in place.
So far it is working very good, no dry hits and I can vape the whole tank
Give it a try, it could work for you also.