All I can say is "give it a try".
I have seen with other old processes that ammonium thiosulfate tends to bleach the image a little, the finer-grained the image the more it bleaches. So with POP, VDB and lith prints I sometimes use a little of it if I want to clear the highlights.
Since cyanide has an even greater affinity for silver than thiosulfate does, I would expect it to have the same effect - only more.
There should be no problems with image stability or longevity when using ammonium thiosulfate instead of sodium; and it's much better than potassium cyanide with regards to photographer longevity.
You could try a "rapidized" sodium thiosulfate: Add a little ammonium chloride to the sodium thiosulfate. My OF-1 fixer is based on this, and works fine with most silver processes (and clears the highlights in POP and lith prints almost as much as TF-4).