Let me remind you that if you have a negative that shows the shadow detail you want but is low in contrast, you can bleach in a ferricyanide-bromide solution and redevelop in PMK, Pyrocat HD or even a simple hydroquinone-carbonate solution to produce a stained and tanned negative which contains the original silver plus the stained image. This is especially effective when you are printing on blue sensitive graded paper. If one application doesn't do it, it may be repeated, BUT the tanning contracts parts of the gelatin and repeated tanning will sometimes cause strain cracks in the emulsion.

The same bleach you would use as the first stage of sulfide sepia toning is fine. Bleaching goes to completion. The redeveloper should have little or no sulfite. Since the development also goes to completion, there is little requirement for exact measurement of ingredients. I have used 1 teaspoon each of hydroquinone and carbonate in a pint or 500 ml of water. Needless to say, it doesn't keep. You could make enough of separate hydroquinone and carbonate solutions for a session and mix them in equal proportions just before use.

Catechol may be used in similar fashion, and so may pyrogallol. The stain colors will differ. Of course, if you have PMK or Pyrocat HD on hand, you may use either.

The whole process is carried out in room light because the film must be fully exposed in order to redevelop all the silver. If you are going to use a developing tank, be sure the bleached negative is thoroughly exposed. You should probably do one sheet in a tray to get an idea of how long it will take. Over development will do no harm.