RE: engine setup for the winter
You need to tune to outside temps, colder outside = denser air and more oxygen entering the cylinder, this requires a richer air fuel mixture.
I.E. richen (turn out) the HSN.
Fuel has nothing to do with outside temps.
Before a discussion insues, here's a vid of me running my K5.9 on Byrons 20/12 in 9F temps...
Same fuel I run in 100F temps.
[youtube]http://www.youtube.com/watch?v=NW_goF4T3cA[/youtube]