My only suggestion I will give you.
Don't make symmetrical castles. My castle is completely asymmetrical like a real castle. In the event an intruder breaks in my castle he won't know the layout because it's completely mazy. I would have the upper hand.
When you make a symmetrical castle your layout is completely obvious. Any invasions your castle is vulnerable to attack.
Lots of real castles are symmetrical, even in the layout of interior rooms.
Assymetricality is just as likely to cause problems in defence as you can't always defend one side as easily as another.
Most assymetrical castles are designed such only to fit and take advantage of the land they are built upon.
Also, making the castle a maze is loving pointless, because you only hamper your own ability to get around it quickly.
If an enemy has breached the walls of your castle then maze or not, you're likely forgeted. Only another bastion/fort in the castle will help.