Just got a reply to my email. Now I am more confused. It is $8 for one liter worth of amidol (I'll grab enough for a few sessions), but he offered me two different fixers.
32 ounces dry measure Sodium Thiosulfate Prismatic Rice Crystals per each gallon of water. Mix at around 90 degrees. We mix 10 gallons at a time as a stock solution.
For use: To each 1/2 gallon of fixer Add 25 g of Sodium Bisulfite.
Fix for 30 seconds. Turn on the light. Inspect print. Fix additional 3,5 minutes (4 minutes total).
Sodium Thiosulfate without bisulfite Use for 4 minutes.
which one do I need?