Vaporkings has the Russian in stock as of last night. I bought mine from there, as well as a bunch of other gear. Always excellent service, and fast shipping.
I also have a clone Nemmy for work, and a real Nemmy for home. I bought the Kayfun clone with airflow to go on the work Nemesis, but it has proven to be a disappointment. It leaks and whistles and doesn't taste quite as good as the real Russian. I now use the clone as a test unit, just to play with. If I find something worthwhile I will do it on the real Russian.
The Nemesis clone is really solid for the price. The machine work is really good, but the switch is quite janky. I compounded the switch, lubed it well, and installed the magnet switch upgrade in it. It is totally acceptable, and at 101vape you can get it for $30. It is a winner for that $.
As far as batteries, it depends what you are doing with regards to your build. I have the 30 amp sony for sub ohm builds, but I find that I like 1.5-1.7 ohms on my Russian. If I am looking to carry it out, I like the super tiny 18350 mode. I use the AW18350. But in general, I tend to keep my 18650 Sony or Panny in it.