need help with a building for 2 players

I need to build a tower for 2 players.
how tall should I build?
how big?
Of course it needs to be safe.
Please help
thank you

I’d build only metal doors for 4-5 stories, then Put everything you own in the top stories. Then maybe a small fortification around the bottom story.

My 17 story base, metal doors on every floor, was raided last night. Next time I’ll have to go 40 stories.