How can automatic processing be estimated in an editing task?
What do you mean exactly with 'processes'? If you're thinking about actual movements made during editing (i.e. tiping), this science paper might help. Very simply put, they showed skilled typist have two kinds of control processes, one conscious and one unconscious.  

(Science 29 October 2010: 
Vol. 330 no. 6004 pp. 683-686 
DOI: 10.1126/science.1190483)