When using my Longbowmen tactic from MTW using an all-archer army (IE: Foresters or Chosen Archers) plus a cav or two, I keep them all in double rank. If the enemy cavalry breaks through the volleys and hits the first rank, the second rank is still able to take up the fight until the cavalry breaks and runs. Obviously, all of them are set to not skirmish, and set to guard mode.



When defending bridges with infantry, I use a custom-made U formation. The main infantry (IE: Phalanx) will be five or six deep, and facing the bridge about one unit length back. Then a unit of hard hitters (or phalanx again) will flank the open gaps on the side.



When the enemy hits the main unit of infantry, the supporting infantry will close in and wipe out the enemy from both sides. Sure-fire way to rout a powerful enemy.