I did some testing with HP5+.(posted 8610 days ago)It worked I suppose as intended with a strong proportional stain and no overall staining. The recommended development time was in the ballpark; the developer modifications done to prevent excess aerial oxidation appear to have worked.
Results were, to put it bluntly, horrid. Compared to a "standard" developer (D-76H 1:1) it was lots grainier while acutance was way down. While it probably would have printed on graded paper ok, the stain caused quite a bit of highlight compression (grey muck) on VC paper.
Now to put it in perspective; I think it would've been just fine with 4x5 and larger formats and for alt. printing, especially when faced with an extreme subject brightness range. But 35mm was a non-starter.