I built for 80 hours during the 2 playtests. My simplest FOB design.

preview.redd.it/i0z8vlop9foh1.png?width=921&format=png&auto=webp&s=39786dd6e67d841a18aa2b760728b7fa138d8a24

It is pretty simple, easily defended, and can have multiple layers of complexity added once the initial build is complete.