I have used divided d23 quite a bit. Regarding development time I think a good starting point is to take the normal development time for solution A (i.e. d23), and half it. Then develop for that time in both solutions. One needs to realize that the more development is done in solution A, the less compensating effect takes place and the more the negs will look like normal contrast negs. Using the above times the negs do look a little thin, but this is the intended result - a low contrast negative.
I find it a great technique for very contrasty scenes where one wishes to retain detail in both highlights and shadows, but it does not give good results for normal or low contrast subjects.