I don't have an Avocado but do use Genesis style tanks. I don't use anything but mesh, ekowool or ss rope in them. (#nocottoninmygenny)tl;dr What's the technique folks are using when wicking the Avocado with rayon?
Looking at all the videos out there on it, I would say trim your tails and push them down to the bottom of the tank. I think the Ceramic block only fills one hole so airlock should not be an issue. With a dual build, make sure the Rayon is not compressed as it comes through the deck holes.
Looks like a great tank but might pour out if laid on its side or upside down in a coat pocket.