Personnaly I use a 63x63x63 3D-lut with an insane amount of decimals, because G’mic is not impressed and works at the same speed, more or less. So bigger file does not hurt the workflow.
Besides, I did a test with a poor 3D-Lut (like 8x8x8) and a big one. Then I opened the 2 results as layer with gimp, and the above layer was set to “difference”. And yeah you see them. especially in the borders of objects/persons, the silhouettes. But all picture is concerned.