I haven't tried the new Delta 400 yet, still using up my supply of the old stuff.(posted 8520 days ago)For the old stuff I have found that PMK at 70 F for 6'20" produces an EI of 250. This produces a zone I density of 0.09 and a zone VIII density of 1.16. I also shoot 120, same dilution, same agitation schedule, same stop, same fixer, same afterbath, same wash.
I have a Kaiser MG enlarger, uses a halogen lamp, seems pretty contrasty. If you use a diffuse light source you may want to shoot for a higher zone VIII density. (I bet you already knew that.)