Oh and aure, I don’t know how to format the april tag finder output since I don’t even know how to run it (see previous post). 
But if the output file can be formated according to RC specs, it should be straightforward via Workflow - Import & Metadata - Control Points. The format is very simple, just image path/name, point name and two pixel numbers (not sure if horizontal or vertical comes first). It will be more tricky to use them as Ground Control Points, which is what I am aiming for, since I need to include coordinates from a different source for that…