D-19 was designed for primarily scientific photography in which a straight-line characteristic curve was desired. I do not recall any data being given for its use with films designed for general or pictorial photography. However it was used for "law enforcement" and low-light photography with two different emulsions for which I have copied data sheets, 2475 and 2484. I used it with the 2481 emulsion for infrared photography as well, but could not find the data sheet for that.
D-19 was used almost as standard for astronomical applications for both imaging and spectroscopy. The emulsions used for those applications were 103a-O (blue sensitive) and 103a-E (red) on glass plates processed in trays, usually for 4-5 minutes at 20C. The original Palomar sky survey was made over a period of years with the 48" Schmidt camera using 14" glass plates bent to conform to its curved focal surface, and processed with D-19. I found that it was also useful with P-3200 for recording green-phosphor image tubes. The result obtained was a straight-line curve with little toe and shoulder, and gamma near 1.0.
D-19 and D-8 were designed as high contrast developers to form a rough series of contrasts from D-76 upwards through D-8. I find I appear to have no easy to get data sheets, but will keep looking. I do have both formulas.
What I have found is about 3" of text in an old Kodak pub. It just about repeats what is said above. I can find nothing new to add. Sorry. It does mention the "contrast series of developers" which are D-8, D-11 and D-19 and the book includes short blurbs on them as well.