I'm listening as always.
The article is also at thesaratogaspecial.com. I think it ran on 8/4 or 8/3. Its definitely a subject worthy of further research, but I think that you'll be reliant on the subjectivity of horsemen and people in charge of maintenance over the years. Its not like you can go to the Keeneland Library and substantiate claims of various tracks' depths. However, given what Mr. Porcelli said to me, its pretty obvious that track surfaces have changed through the years and frequently change during the course of individual days.
Maybe I'll speak to him again before next year's meet, but I just got engaged so I've got more pressing matters about which to worry.