Might try a balloon tank similar to what Minnesota Modeler uses on his 1/2A's.   

I didnt make top of fuse. removable, so now there isn't alot of room between engine and former.

On lthe balloon tank, you don't put enough fuel in it to make it a pressure tank.   Done right it has  consistent engine run from start to empty.

Well I would suggest you do a search for balloon tanks in the 1/2A section or contact Minnesota Modeler who is a member here.   I use silicone tubing, two peices on a copper tube,  the tube fits the neck of the balloon.  The peice of silicone tubing in the balloon goes the depth of the balloon.   I have notches/holes cut in the tubing.   The tubing out side the balloon goes to needle valve nipple of course.  When filling the balloon try to suck all the air out of it.  Then put in the fuel.  Invariably there will be an air bubble that when balloon is held right can be sucked out with the syringe.  Pinch off fuel line and hook to engine.  The balloon should not be putting any pressure on the fuel when in the fuel tank area.   It takes practice getting the right amount of fuel in the balloon and the air out.   When the engine uses up all the fuel you will find a collapsed balloon waiting to be filled again.   I did the tets on the bench before putting in the plane.   Needle settings stayed vey consistent.

Thanks, guys...as the plot thickens... More to think about, though.