I tried doing my DD-X experiment today, but found mystery film in my film holders, so I decided to practice with them to get back into the swing of things.
Turns out it was HP5+, and Michael was correct that DD-X builds stronger highlight density; less shoulder than Xtol. So I ended up using Xtol 1+2 with great results.
I shot and processed all ten mystery 5x7 sheets today, and will likely load some Foma 400 in the next couple of days, and will report back here what I find regarding pushing Foma in a conventional developer, just as comparison.
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh