I have a GW 335 w/ twin 425s and 300 gallon fuel capacity. I am in the initial stages of trip planning to the NE canyons and have a couple of questions. I am about 115-120 miles from the canyons one way. Given a burn of 1 mile per gallon I'll need 250 gallons round trip. So I know I need additional fuel via a gas bladder. Thinking 100 gallon bladder would be enough as I'd then have 150 gallons in reserve. That said, does anyone have experience w/ a gas fuel bladder and if so any hints or suggestions. I am concerned about safety with gas (vapors) and wondering how exactly I am going to transfer the fuel (gravity, pump). Thanks in advance for your help.