Your well to tank numbers... WTF? If it took then energy of 5 barrels of crude to make 1 barrel of gasoline there wouldn’t be so many people pissed off about corn ethanol. I have come across 80% for gasoline and 84% for diesel on more than one occasion. A good source are ethanol to gasoline energy analysis.
http://www.transportation.anl.gov/pdfs/TA/354.pdf (Slide 4)
Increase in fuel used to fight emissions. This is a hard number to pin down so I will be generous and say it’s a 25% increase for the purpose of your argument.
Now the math:
1.25 x (1/0.8) = 1.5625 increase in emissions due to extra fuel required.
1/1.5625 = 0.64, 1-0.64 = 36% reduction in emissions to break even. 36% is not hard to do on any type of emission except CO2 which is not a pollutant but a green house gas and cannot be reduced with emission control equipment.