But I've got rivers of condensation running down the inside/starting to run down the outside. Seems like it needs way more air than what a 2mm gap will provide.
Are you definitely getting your carbon and nitrogen ratios right? Maybe put more cardboard in. What sort of temps are you getting and how full is it?
My temps start to drop when it gets above 3/4 full.
Here's a pic of my vent yesterday.
But I've got rivers of condensation running down the inside/starting to run down the outside. Seems like it needs way more air than what a 2mm gap will provide.