Primus Inter Duces, that's a great post!

Deploying missile units in square formations so they can maneuver swiftly while maintaining cohesion. Also makes it easy to gradually "envelop" oncoming enemy because the squares farthest from the center can easily turn and fire after flanking.
This sounds like a good advice!

Using bait and switch methods with long-range missiles and cavalry to draw enemy skirmishers/missile units away from the protection of the main battle line
I use a similar tactic to lure enemy cavalry away from the main battle line.
I move slingers, in loose formation, way before my main battle line, having cavalry (or fast-moving spear infantry) in close support. Taking advantage of slingers' long range, I order them to shoot at the enemy cavalry units, or, even better, the enemy general. The result is that they kill a lot of cavalrymen and that usually makes enemy cavalry charge at them without infantry support, allowing my own cavalry to defeat them easily! That way I get a really big advantage for the rest of the battle.

Capping the T' can be useful when an enemy sallies forth.
This is a naval tactic, isn't it?
By that I understand that when an enemy sallies forth, we place our missile troops in a line, facing the enemy town, shooting at them taking advantage of the bottleneck at the gate.