Walt said he does an 8oz and 9oz tank which should be enough in most cases. I took some measurements of a tank I thinking of having Walt build and it could be either 10oz or possibly 11oz size tank.
I had some trouble with fuel satrvation with my 8 oz slant tank so i went with a hopper between the motor and brass pass through that holds the cf rod in place.I see others doing the same.it works REAL well and cheap.