I posted this colony earlier but things have developed since

I replaced the big wall of embrasures encircling the base with concrete slabs from a mod, both to reclaim some steel and because the concrete slabs have ridiculously high HP

I also expanded the bottom right a bit, which was a good call because a mech cluster landed on that side not long after. Those 2 big CIWS turrets aren't nearly as powerful as they look, sadly.