What I hope to use, if I win it on ebay, is a 4-5 psi, 30 gph pump that should let my tubing prevent drawing air because it's not pulling so hard, and if it does, it will just go into the surge and out the top. And like the old statement that electricity takes the path of least resistance, which has always bugged me because it's WRONG, It follows ALL paths!!!, not just the one with least resistance. Same with fuel flow, it may get some air but it will still draw fuel and pump it into the surge tank. I plan to put a couple of switches in the pump circuit so it turns on when about 1/3 empty and off when full, so it should only pump about a 1/2 gallon and rest until that 1/2 gallon is burnt. Worse case scenario, the pump can't get gas because of the slope, I have a gallon in the surge tank and I draw from the bottom.
Other good things: if I need to make a fire, boyscout style, One Match and some GAS, I can get some from the drain valve, I can also get rid of any water that may get in the system and if I run into a fellow tourist who has run out of fuel, I can drain some into a cup, can, or bottle for him/her quite easily. I quite like this system and see no real problems, you could even skip the switches and just let the excess flow back to the main tank out of the top.
Kinarfi