A Quick layout for sieging up Blue keep defensively.
Balista is next to useless here unless you can guarantee a clear line of sight where you can click on your target. In fact, the only easy place I can think of is the top of the tower when the enemy has their siege on top of outer walls.
I’ve labelled where Enemies are likely to hit with shapes. Most areas will be within the range of at least 2 defensive sieges. As you can never know where 25+ people will decide to start their attack, you need to be on the ball and place some more nearer to them, either as deterrent or bait.
If they go for south/spawn/double gate, use catapults or trebuchets in lords room and try to either aim into the gap above the inner gate to hit the outer gate or hit the outer edge of the wall from the top. either focus on knocking them over or supply draining, if there’s more than one trebuchet, organize it between. Ideally, rocks hitting them will help if a tag comes from spawn to push.
North gate will likely to be Omega Golems these days, Rams will have Shield generators with them. Ideally, there should be roamers putting Supply Traps in the approach chokes to gate to help deter attackers. Trebuchets on inner gates can either hit the inner side of the outer gate or just over the top. Again, not much good if enemy brought shield gens.
Inner gate trebuchets can hit the towers if they have fallen, supply full enemies will likely launch their attacks from them in full PPT mode. If the enemy is occupying the towers and managing to hit the inner wall trebuchets, build one up on top of the lord’s dome.
There is a catapult spot on the left/west side of the keep, under the corner of an arch/bridge in the ruins, next to the cannon corner where siege will have trouble hitting. As this is a sneaky spot, not many enemies will be there to avoid detection. Best idea is to jump on them with some allies.