I've been trying ACROS and results are encouraging with Dixactol, PMK and 2 baths. Will stock up with APX 100 5x4 anyway just to be on the safe side but in the long run I'm moving to 8x10 for most of my b&w work. Barry Thornton wrote a handy piece on ACROS in Ag magazine a year or two back and there should still be back issues around.