Thanks,
Corelz,  Sorry to hear everybody is sick,  get better soon. 
It depends on the situation,  but typically I shim the side in place plumb,  1/2" away from where it need to reside.  Then I use a scribe pencil set at 1/2".  I rough cut it, leaving the line, then turn it on edge and belt sand to the line.  Hard to go wrong if you don't go past the line. 
Scribe molding is not in my vocabulary.

Figuring out how to do something you have never done is what makes a good challenge.