I meant to say to me it was literally the first thing I tried, to queue them both, after I saw that one blocks the other.Well, my way of building a new colony is to directly transfer pops up to 5, upgrade the shelter and then fill the planet completely. If you do it like that, it is quite naturally the opposite. I only realized that being able to build both was unintented when I got bored and wanted to build spiral hubs on all previous colonies.