Give the Hayes 'O' ring type tank a shot:
http://www3.towerhobbies.com/cgi-bin...K830&P=RF#tech
These tanks are far easier to assemble, are more reliable with no leakage problems from age or setting and withstand repeated removeal's of the plug. They are for two line systems and what I use on almost everything except for a few tettra bubbless types for some competition RC types and a few controlline airplanes.
You also may be able to use the 11 ounce if you prefer with some trimming described by Spoondude.
John