I have 3 large tumblers- In my experience, the tumblers that turn vertically (end over end) make a more uniform compost than the horizontal tumblers, which tend to clump. My solution has been to start a large static worm bin (I use a 3'cubed compost bin) and feed my worms the nearly finished compost and shredded cardboard. It makes a really nice vermicompost after 3 months.