I think I'm going with a Dubro 50 oz rectangular tank, and use the BVM high-flow fuel cap with 3/16 brass tubing for the larger tygon. I tried fitting a 1.5 Liter bottle, but the dubro will be easier to install. I placed a vacuum tube extension in the picture just to show the location of the wing tube. I'll build a simple frame. As you thought Chris, I won't be installing a cockpit, so it gives me more options for internal installation.