Two other work arounds to this problem. First the larger the tank the longer the internal flex line and therefore the more flexable it becomes. So moveing perhaps from an eight ounce to a ten ounce just may take care of the problem.
If that is not desirable or possible then give consideration to how you have assembled the bung plug. How much of the solid through tube do you have protruding past the backside of the bung plug. An excessive protrusion here will rob flexability of the internal pickup line. I like to keep these protrusions quite short on the smaller tanks for this reason.
The other extreme of this consideration is with very large tanks the fellows will sometimes add solid sections of tube to the internal pickup line reducing flexabiity to prevent the pickup tube from flopping forward and cutting off fuel during a firm arrival.
John