@Alan Johnson I have followed this thread with considerable interest. So much so, that per
@Raghu Kuvempunagar's observation #45, I am going to try this using D-23 plus the requisite odds and ends. I am affectionately calling this developer
Creepy Crawley
Have spent many hours over the past 4 years or so exploring many variations of semistand and EMA with a variety of developers, I have a few observations you may find of use:
I too have noted that some variations on this theme can trend toward "harshness". Mostly, what I found is that using
less agitation,
less standing time seems to help this. In theory, so should higher dilution, but you can get to a point where the acutance is so high, the image looks more like a cartoon drawing or graphics art rendering than a photography. Of course, this can be a creative tool in its own right. The point is that - at least in my observation - the harshness is a combination of too much highlight density and excessive acutance.
I'm also somewhat interested in whether the 10^-3049392 mole of potatssium iodine (I made up that number

make any difference with modern film. My smallest scale has 1mg resolution so I made a stronger solution of KI than called for, just so I could reliably measure the chemical (50mg for 250ml of water). I plan to dilute it per requirements.
Upon confirming with my friendly, neighborhood AI, the claim is that KI is no longer needed with modern films, but does no harm. I plan to use it for the Creepy developer only because - if it works with my initial test victim, Fomapan 100 9x12 - I have a goodly stash of 2 1/4 x 3 1/4 Efke PL100M and Adox CHS 100 II I'd like to try with it.
Film at 11 (or whenever I get around to it) ...