Added 42 minutes later
I tried it at the beginning and did a blitzkrieg – Day 6, Week 3, Month 1 – I attack a Castle and find: 54 Archers, 18 Red Inquisitors, 11 Tournament Knights, 150 Landlords, 15 Blood Griffons, 2 Lava Golems, and a fortified Castle. Plus, an additional stack from the Tower – 220 Warriors.
I have 50 Berserkers, 7 Bone Dragons, 33 Gnomes on a Bear, 95 Javelin Throwers, 112 Spear Masters, and 89 Gnomes.
My Javelin Throwers deal 1-3 damage to Archers, and the Archers deal 89-95 damage to Javelin Throwers per shot.
So, go away; 600 Javelin Throwers are more than enough. Do the math: 100 Javelin Throwers kill 1-3 Archers, 600 Javelin Throwers kill 6-18, but by the time you gather them, he'll have 30 Lava Golems.
Forget it; I'll try replaying, and I won't do a blitzkrieg. Maybe the script for the Castle only triggers after the hero is freed. I'll try to explore everything I can in three weeks and then proceed based on the circumstances.