What's an easy way to get A LOT of duration out of a glow engine for a .25 - .40 size plane? I'm not looking to do exotic gas conversions, I'm not trying to cross the Atlantic or anything. I'm looking for 45 minutes to an hour of sporty performance with throttle management. I was thinking of running a .25 on 16 oz., but although I can probably figure out a way to manage the extra fuel weight, the shift in cg from full to empty might be extreme, so I'm looking at ways to accomplish this with less fuel, maybe 10-12 oz max. A .30-.40 size 4-stroke? A simple mod, like using a different carb on a certain engine? Any tips are appreciated, tell me how you would do it. Thanks!