Anchell/Troop's Film Developing Cookbook mentions DK-50 1:3 as well as BJ Dilute DK-50, and indicates it gives close to a straight line curve without "blowing out the highlights" and suggests the higher dilution for modern films (possibly even 1:6 for TMax if I remember right). But alas, no suggestions on starting times. There outta be a law...when a book recommends a developer it should have to say how to use it, at least as a starting point! DK-50 is recommended for subjects of limited contrast range such as studio work.
This is the reason for my interest in the developer at this dilution.
Ian: Thank you for the BJ recommended times--it gives me some starting points.