For your game, stand at +1.
Mike is right. Basic strategy is to hit (A,7) vs Ace. The only exception is single deck when the dealer stands on all 17s. In that game, BS says stand.
When the dealer hits soft 17, this is not a close call at all. Wong gives the index number for single deck H17 at +17. He does not provide an index number for 4 decks, which means the value is higher than +20.
In an S17 game, this is a much closer decision. In one deck, the index is 0. In 4 decks, the index is +1. So, stand at +1, hit at anything lower.