If I can request a constructor for a colony, when it arrives adjacent to that colony, I can then manually move it into place to, for example, maximize its mining capability, then create a starbase. I could also request another constructor with the intent of creating a starport. After the starbase is created, it can then request its own constructors as before.
Doing it the current way, I'd have to place the destinations for the constructors manually or wait until they're all made to put them in a fleet. Manual destination placement can involve a lot of scrolling of the map if the colony's star is a long distance across the map if the original colony ship hasn't arrived yet.
Does creation of rally points work now? I would be able to do it that way, Go to Rally Point 27, for example. I haven't been able to figure out how to place rally points anywhere I want on the map.