I came across another tanning developer formula recently. This one is from Focal, and it is quite old. Since I'm still waiting for my darkroom to get built, I haven't tried it, but it may be interesting.

Focal tanning developer

Pyrocatechin 2 g
Sodium sulfite (5 percent soln.) 5 ml
Sodium hydroxide (5 percent soln.) 10 ml
Water to make 1 l

Develop 15 to 20 minutes

The developing recommendation was no doubt for old style (1950s) films.