I'm curious. Is it ok to have the lids on the jars whilst in the kiln?
I keep them closed because it's easier for me to control the humidity in a sealed container. I open them once a day, pour the tobacco into a container, air it out for a couple of minutes, moisten it if necessary, and put it back in the jar and the chamber. The only inconvenience is that you have to open the jar immediately after taking it out of the chamber, and if it starts to cool down, it will be difficult to open.