Martin,

I use the same strength mixture of stop for paper and film. The only difference is that with film I dilute this to 1-3 (stop to water). The reason is that I use Pyrocat as my film developer and the dilution alleviates any tendency to pin hole film. This is not only true for Pyrocat but also for the ABC pyro formulation. I discard my film stop bath mixture after each session.

Along the lines of fixer. I use plain hypo (sodium thiosulfate mixed with sodium sulfite) for paper. Some recommend using rapid fixer (ammonium thiosulfate) for film since film has silver iodide as a componant of the emulsion. This ingredient is more difficult to fix. Good luck.