I like that article - I long wanted to see what the markets do on average hour by hour. It always "felt" to me that around ~2:00 (Houston time, market closes at 3:00 Houston time), the markets tend to start going up more than other hours of the day. And then apparently they just keep going up and up on average at night. Consistent with my testing.
So I think the article just further proves the point, putting tax considerations aside, if you want to maximize your returns, start buying late in the trading day, hold overnight, sell first thing the next morning, come back to buy in an hour or two before close. Rinse and repeat and PROFIT.