Maybe mixing my own developer would be the way to go. Can you point me to the recipe you used?
distilled water 750 ml
triethanolamine 6 ml
sodium sulfite .2 grams (published formula was 1 gram)
CD-3 5 grams
Potassium carbonate 30 grams (published formula was 40 grams)
sodium chloride .5 grams
add distilled water to make 1 liter
This developer has no odor like the Kodak RA-4 developer since it lacks the smelly preservative. The sulfite is the only preservative but if it is increased the contrast will lower, and you may want to experiment with that. The developer is VERY sensitive to changes in it. Hydroxylamine sulfate may work in place of the other preservative but I have not yet experimented with it. The upshot is that this developer has a short shelf life, probably less than a week in full, glass bottles. Therefore it may not be suitabe for your purposes. I mix it as I need it or keep it for a few days. You may want to try simply lowering the pH of regular developer with acid, adding very carefully in small increments.
I have experimented a little with simply adding sulfite to regular developer but the image quality just seemed better by lowering the pH and best with the above developer.
I use it at 68-75 degrees for 2-2 1/2 minutes. You should test for other times and temperatures.