Just the (gray scale in your case) bar that’s at the bottom right corner of your FA screenshot, so I could get an idea of the magnitude of the FA intensities I’m looking at. Thanks for that! From that screenshot, I can already assure you that you don’t need the -fa option to the dhollander algorithm; the default value (of 0.2) will work just fine out of the box!
The only thing I forgot to ask to show was an ADC map, and/or some information about the environment the brain sits in: you mentioned it was post-mortem, but does the brain still sit in the animal, e.g. suspended in CSF? Or does it sit in some other fluid? It seems to still take on a shape and even position that hints at it at least being suspended in a fluid; but it would be good to know nonetheless (and if not CSF: what fluid?). But again, and ADC map would give me the information I’m after just as well.
So far, all conditions are in place for the dhollander algorithm to work out of the box, without any special options. If you could run it, and specify the -voxels option to get the voxel output, and potentially screenshot that in the way described here: Multi-tissue CSD - #2 by ThijsDhollander , that would immediately let me confirm (or deny) that it worked well, and provide you with advice on how usable the output is, and in what way.
But just to be sure, and ADC map would definitely be useful as well to confirm a thing or two.