Well I have just done some split grade printing of black & white prints, and I am super impressed. I use a LPL 45 enlarger with a colour head, and expose the 0 grade first and then the 5 grade next. During the 0 grade I can burn in whatever is needed, and this is very forgiving and easy to do.
Basically the process involves exposing the paper to the 0 grade filter to produce the best highlights, then the 5 grade filter to produce the blacks. Prints look really superb, fully toned and nice blacks and highlights. I don’t know what grade is used, but it is the right grade.