2 over 1NT is artificial and game forcing. Two-way is super if playing weak notrumps, so that a 1NT rebid by opener shows extra values.
Details are below with a few interesting tinkers.
He claims that it doesn't really matter which of the first two is highest priority, and some others prefer to show 3-card support first, while others prefer to bid hearts first. Ed Davis came up with some tinkers to this to add accuracy at the cost of memory. Here they are.