This is the best suggestion that I have seen, use a screen shot in the back ground for the feet (at worst it would only have to be shot once or twice not repeated use.)   Isn't it common to use things like that as part of theater these days? 
If you are looking for a credentialed consultant, have you considered calling a friendly Industrial Hygiene Professor?    A quick search of ABET accredited Industrial Hygiene programs showed Hunter College of the City University of New York as having an IH program.