My experience has been that you can split-print any negative with advantages over printing on graded paper. With a thin negative, the exposure will use more blue and less green light. You could have a situation where part of the print (or even the whole print) recieves only the blue light (making it roughly the same as a grade 5 paper). With a dense negative the exposure will use more green and less blue. The great benefit is the control of local contrast and in my opinion it simplifies the printing process. Now if only they made a VC Azo.
George