Maybe you can wrap a 3 litre airpot around a 1 litre base from another airpot and that could give the roots more height but still less diameter than a 3 litre?
Maybe you can wrap a 3 litre airpot around a 1 litre base from another airpot and that could give the roots more height but still less diameter than a 3 litre?

Sweet!
nice tidy set up bro!
What are the little black puck looking things on top of the pots?