gradate vs size up

gradate

verb
  • To bring to a certain strength or grade of concentration. 

  • To change imperceptibly from one gradation of tone etc. to another. 

  • To arrange in order of grades. 

size up

verb
  • To evaluate; to estimate or anticipate the magnitude, difficulty, or strength of something. 

  • To wear a larger size of clothing. 

How often have the words gradate and size up occurred in a corpus of books? (source: Google Ngram Viewer )