I had read (don't ask me for sources, other than RFF posts and various folks' blog posts) that a washing aid should be added to the Tetenal press kit stabilizer.

I scanned the first roll of negatives, and I'm very happy with the results! Other than a slight yellow color shift, which I can live with, the negs came out great. They're clean too -- the sudsy stabilizer didn't appear to have had any detrimental effects.