I did it rockless, but I love the idea. The creation of the planets bit by bit and analysis of colony viability was a blast to play. The summary from my crew of colony engineers:
Fonda-3 is the worst. It is breathable, but landmass is scant, no native food to be found, and temperature spikes are deadly. A artificial metallic core with no known purpose also leaves us concerned.
Fonda-1 is breathable in a pinch, but we’ll have to subsist on ice bugs and invest in tunnel infrastructure between bases which must be positioned between ridges to protect from intense weather.
Fonda-4 is next best. Breathable atmosphere, but the surface is dangerous (flying beasts, meteors, stray death portals) and an underground base built to be structurally sound will be quite costly.
Fonda-2 is clearly the best choice. Full stop. Requires work with lightning and pest mitigation, but otherwise is a beautiful planet for us. Welcome home, folks.