i want to give catechol devs another go. either a catechol/glycin variation or pyrocat hd (again).i have all them chemicals ready, except the sodium metabisulfite. i'll order new chemicals soon, but it usually takes at least a month for them to arrive and i don't want to wait that long right now. would it possible to mix pyrocat without the sodium metabisulfite? i've read that the s.m. is only for enhancing the keeping properties of the solutions and has no relevance for the image tone. how quick would pyrocat without s.m. go off? and should i substitute it with a little sodium sulfite (not too much, i don't want to kill all of the stain)? and would i need a different b solution (which is less alkaline), for example carbonate instead of the hydroxide?