Hi,
First reply to a post myself.
1 - I would agree with the article that if you can get 1% a month then you'll be doing very well.
2 - How long is a piece of string? That's a very difficult question to answer. From my experience it could be anywhere from 3 to 6 months depending upon a variety of factors. Profitablility has declined but there are still pockets where you can attempt to extract some performance. Look for places where there are capacity constraints for larger players. You will always need to look for new pairs as the relationship of the pairs will deteriorate over time.
3 - That depends upon your input parameters. Are you using daily, weekly closes etc. I don't do intraday mean reversion.
Thank you