Great work on the updated test image @alexfry!
I notice that when incorporating my “spider web” ramps, you’ve kept the grey ramp in the middle. That’s just a linear 0-1 ramp, which already exists elsewhere in your pattern. I think I stuck it in mine because there was some spare space, and it was another thing to make the pattern more universally useful. But it seems redundant here.
Regarding the Macbeth Chart, you are using the “After November 2014” patches from @Thomas_Mansencal’s colour-science for Nuke. While close, these don’t quite match the ACES reference values on page 11 of S-2016-001. I’m not sure what the derivation of those values is. Perhaps @Alexander_Forsythe or @sdyer can comment.