I usually kiln all of my tobacco for two months at between 123°F and 128°F (~50°C to ~53°) in high humidity. I do not measure the humidity, which is kept high enough to keep the leaf easily pliable, since above 122°F, mold cannot grow. I do not spray my leaf for fermentation, but use a temperature-controlled slow cooker (Crockpot), kept filled with water, as my heat source.
I know nothing about adding bacteria.
If you plan to ferment the leaf using the pile method, then you will likely need a minimum of ~500 pounds (over 200 kg) in a cubic stack, monitoring the interior temperature. Leaf is just sprayed with water prior to building the pile. When the center of the pile approaches 128°F (~50°C), then the pile is broken down, and rebuilt with the interior leaf now on the outside. Watch the temperature, and repeatedly rebuild until the temperature no longer seems to rise much. Most home growers do not produce enough leaf to use this method. So a minimum of ¼ to ½ acre (0.1 to 0.2 hectare) of tobacco would be required.
Bob