The bad news is that Everest and CoreTemp don't give you any way to correct for this problem. Since you like Everest, you have to get used to your idle temps being reported differently.
I kind of figured as much, which is why I didn't bother with the calibration uncle. Maybe Everest in a new version will allow for a more specific adjustment of Tj. Max and then I can do the calibration.

Although since the re-application of thermal paste and setting Tj. Max to 100C, I'm reporting temps between 35c-37C and 35C-38C. A little better than the 4-5 difference before hand.