Notes about Unicolour and ACES workflows
The basic idea behind Unicolor is that it provides lossless and reversible conversions between a list of color curves and gamuts. No lUT involved, the preciosion is that of FP32 math. The implication is that you can grade in any curve and gamut you choose, using the "sandwich workflow":
You convert your input media into the grading space/curve. If you used RAW media, frequently the 'RAWparams" effects of Mistika allow to convert stright to your gamut/curve. If the RAWparams controlled codec does not provide the desired grading gamut/curve combination, you can set it to some common format (like P3 gamut + linear light curve) and use an Unicolor instance to convert that common format into desired grading gamut/curve. This is the lower part of the sandwich.
Past grading, you use an instance of Unicolor to convert from the chosen grading gamut/curve into the delivery gamut/curve - this is the upper part of the sandwich.
Notice that Unicolour supports only spaces that can be described in math only as a gamut plus curve. ACES does not fit into this description, plus described in math it is too complex so it requires use of LUT. Also, the ACES ODTs were designed to be output only and does not work well in inverse mode.
For deliveries as by ACES spec, the upper Unicolor node converting from working space (it may or may not be ACES rimaries + AcesCC curve) should be replaced by the Mistika ACES-ODT node. This node combines the input side of Unicolor node, where you can specify your grading gamut/curve, with ACES-spec output side. The node interprets the ACES ctl files installed on the corresponding folder