RE: Savage half tank EXTREME lean problem.
I absolutely love fitting it into the back bumper. Since we run a pressurized fuel system I don't think it will matter much that the tank is below the carb...matter of fact, most on-roads are set up that way. My entire tank is below my carb, my pickup just more or less the thickness of the tank wall above the chassis itself, and I don't have any fuel feed issues.
If you can sort the lines, use position two though. You'll get a good five or ten minutes to get to it if it goes onto it's lid that way.