I cannot take all the credit. The ls guys had a nice thread discussing the theory and science behind it. They settled on 20% being the magic number. All I did was find a table for us 3800 guys that could be used to do the same thing and added 20% fuel to the needed areas. Then I smoothed it a bit and it was a success. I must have gotten it right because I haven't felt the need to change it since then. Have had a few -10*F starts and it took less then 2 seconds of cranking just like it should.