I just did a carburetor cleaning.  Now I notice that my fuel mileage has dropped from 52-55 mpg down to around 40.  I know that some adjustment is necessary.  I read the Carburetor Theory 101 in the tech section and have seen alot of discussion about the white spacer.  Am I correct that in the 101 document the clip position of the jet needle (higher is leaner) corresponds to the Savage white spacer adaptation (thinner is leaner)?  Any suggestions about what adjustments I should make?  I want maximum mpg for commuting.  I probably need to add that I installed a like-new baffled Sportster muffler on the bike, but was told that I shouldn't need to re-jet.  2002 engine and carb on a 2000 Savage.

Now I'm really confused.  Page 2 of the "Carburetor Theory 101" document says, "If the engine needs to run leaner, the clip would be moved higher. This will drop the needle farther down into the needle jet and cause less fuel to flow past it."  So to apply this same principle to the white spacer mod, a thinner spacer would also allow the needle to drop farther down.  Are you sure I have it backwards?

Instead of messing with the spacer, would I get any result from adjusting the pilot air jet to make the fuel mix leaner?  And if I adjust the pilot air jet, is there any other adjustment I should do as well?

What changed?
If mileage changed after cleaning...you may have had a blocked passage that is now opened up.  
Is your jetting stock?  40mpg is very low for this bike.
Stock jets are 52.5# pilot/ 145# main (47.5#/125# in CA).  Is that what you have?

Raising the needle, with lowered clip or less spacer, pulls it out of the needle jet and makes you richer,...worse mileage.
I wouldn't worry about that.