I use Arista Rapid Fixer from Freestyle Camera in Hollywood, and Lowell Huff at Clayton Chemicals, who manufactures it, told me during a recent phone conversation that only 30 seconds is needed to fix Ilford's RC papers in it. I give it a minute nevertheless and at 30 seconds I turn on the light to examine test strips as well as prints, especially the latter to determine if artifacts got onto my prints while the negatives were sitting in my enlarger.