I don’t think construction script can have that real-time update effect u r referring, but tagging along to see if there’s any possibility to this tho.
Closest thing I would imagine is having a parameter that user just drag and increase 1 by 1 so the user can see it (but the whole thing probably would get recalculate everytime u change it).
Another way would be having it in EventBeginPlay instead of construction script, and just simply adding a delay node at the end of each loop. You should be able to see the “slowly instancing” result when u hit the play button.