I use a dual series vertical mounted micro coil on the Russian with an external wrapped wick. When I used cotton the wicks would last 2 weeks before needing to re-wick. I am now using hemp fiber and have a week on it so far. You'll find most any build works great on the Kayfun style rba. I've built this puppy with everything but ceramic, but I keep coming back to the dual vertical as the best performer, smoothest draw with no sputtering, and easiest to wick.
After discovering mico coils I quickly moved away from silica and used cotton primarily. The flavor is better and cotton is so easy to find, plus there is the health concern about silica needles that can impale the lungs once the silica starts to break down. I'm currently using 28 awg Kanthal for my coils, works great for my builds that range from .5-2 ohms on my various rba's.
Once you start building you'll discover what you like best. It's good to try a bit of everything because we all find our personal preferences, but still like to experiment just to see if it will vape better if I try it this way.