Sox output sounds identical to the output from GoldWave (which also has batch processing), BUT: Goldwave has a strange distortion of the fadeout end. So it was a nice find, sox is better - but disregarding the endfade flaw in Goldwave, the sounds were identical.
Here's the commandline I used:
sox pcfile.wav -b 8 -e signed-integer -t raw amigafile.raw channels 1 rate -v 28800
Mine was already mono, you could add mixer -l, -r, or -1 if you want to select left, select right, or mix channels ONLY if the sample is stereo (sox will throw up if it's mono). Put it after the output filename.
Tried several dither options, they did not effect the sound *at all* audibly (I have good equipment). Tried some treble cutoff filter settings that could improve things, but concluded that the above was as good as it would get.