If a Winter Knight with Inhuman Toughness (Armor: 1) wears a bulletproof vest (Armor: 1) underneath a magical duster (Armor 2, 3 uses/session), what is his Armor score? Is it 2 when using the coat and 1 otherwise (no stacking), 3 when using the coat and 2 otherwise (Toughness stacking, but vest and coat not), or 4 when using the coat and 2 otherwise (everything stacking)?