The D-158 formula looks broadly similar to the (Defender/DuPont) 54-D formula , which I have taken to using for the small amount of basic printing I do. Although 54-D dilution is usually given as 1+2 rather than 1+1

On the basic RC papers I use (MGIV, Kentmere VC, Fotospeed RCVC) 54-D produces a "blue" black that I find very pleasing.