Instead of using the gas as a simple batten, why not make a sail that would 
have the perfect wing shape whenever pressurized gas was injected into it?
Adjusting pressure for varying wind conditions. For that matter, simple 
pressurized air would work. A small 12 V compressor mounted on the boom with 
a quick connect and another on the Genny's furling system. One push of a 
button to add pressure and another to release it. A miniature pump wouldn't 
add much weight and as long as you weren't try to pressurize a tire they 
would work fine and not add much weight. A simple 12 volt line going to the 
power panel would handle the juice for it.

Rummy