Ian - I think a lot of the recent popularity of the notion of using water baths is a combination of the "Book of Pyro" suggesting the use of the alkaline afterbath (used PMK developer) and Anchell and Troop's "Film Developer Cookbook" recommendation of an "all alkaline" film development process. Bill Troop suggested the use of waterbaths instead of stop bath with his alkaline fixers.

In a phone call I had with Bill Troop, he told me that a buffered stop bath was the ideal way to use a stop bath. By adding sodium acetate to an acetic acid solution, a buffered stop can be made. It has a much greater capacity than regular stop as it has a greater acidity, yet it has a higher pH than a simple acetic acid stop. The pH can be about 4.5 to 5 and stop film much faster than regular stop baths. I asked him why he did not promote that idea more in his book, and I believe he replied that there's only so much room in a book, and that he thought the average darkroom worker would not want to go to the extra expense of making buffered stop bath, given how inexpensive regular stop bath is.

So I followed the advice of a "Master" - I now use buffered stop bath by adding sodium acetate to water and then adding acetic acid to the solution until the pH is about 4.5 to 5.