Hi Sam,
Thanks for resurfacing this thread… which I see wasn’t completely answered.
For making a DCDM in Resolve 15, you should use aces_cc project settings. The Output Device Transform can be set to a g2.6 color space for grading, then switch the ODT to the DCDM (or DCDMP3clip). In the renderTab use TIFF RGB 16b not XYZ. The ODT version uses the proper scaling for the DCDM which the XYZ conversion in a render does not.
There is one caveat, the conversion in the DCDM ODT assumes the D60 ACES white point was used for timing. Equal value RGBs are assuming an output of D60. If a D65 was used for the adopted white, the conversion matrix from RGB to XYZ needs to be slightly different. I do not see how this is handled in Resolve and I assume it is not handled.
Validation of the output should check for gamma (2.6), gamut (reds are halved and orange), and scaling (the peak will NOT be 4096 in all three colors).
I think the different white conversions can be handled in the DCTLs that are in a different thread. But it is the same idea, don’t use the Resolve XYZ for the output conversion to a DCDM use a direct formula if possible, and just put the render tab in pass through of ‘RGB’
I haven’t searched for good documentation on this, but I think it may not exist.
Jim