I think that a lot of people just get worried about miners attempting to use old designs when they are going to prove a losing proposition for those attempting to make money doing it. I honestly think that he was attempting to look out for your best interests and advise you that if your plan was to make money that was not the way to go about it. I would also like to hear the answer to your question as it is still valuable. Even if the rigs no longer produce the profit they might once have the intellectual puzzle of how to get the most out of them is still interesting. It is like wondering how to make the best wind up clock. Sure we have much better things out, but it is still interesting to think about. Unfortunately I can not really give any useful information on the topic. I hope that someone comes by to answer and I wish you luck in your endeavors to work on it.