Segd's army is quit good, but I would get more of:
Medium ladder 250+ almost everyone can bring one which make them useful
Stakes and siege shields 35-45 good cover but brake easy so get a few of them
More blunt 1h
As he said 100-150 0slots 1h
And more throwing weapons, they tend actually I would get a 150 of those
And of curse it also depends a lot on which castle you attack, some demands more ladders and some catapults and siege towers. So try to choose the gear depending on which castle/town you attack