Switching away from basic strategy once the TC passes a set value.
That set value is the index: at a TC (rounded down) at or above it, take the stand, double or split side; below it, the hit side. Example: 16 vs 10 is a hit in basic strategy but a stand at TC 0 or higher, 15 vs 10 stands at TC +4 or higher, and 12 vs 3 at +2 or higher. Learn the published Illustrious 18 values.