Dragn, one of the reasons I don't like "stir fry strips" of beef is that they don't bother cutting across the grain. Also, the pieces aren't often uniform. But, I have used less tender cuts of meat, cut across the grain and velveted and they came out beautifully tender. Stick the chunk of meat in the freezer for 20 minutes or so, with a loud timer. It's easy to cut thin slices against the grain when the meat doesn't wiggle.