Joe,

There was a post somewhere on Bob Szabo's CW forum about using Ammonium Thiosulphate as a fixer. Unfortunately after changing software much of that forum's history is gone. As I recall, the gist (once it went beyond the "use the traditional method...") was that you could use ammonium thiosulphate with no major repercussions. Maybe once I work through the 25kgs of sodium thiosulphate I recently bought, I will give it a try too...