> But until we can show the "whole program" running, to management progress seems to be binary. (It either works or it doesn't.)
That's insufficient communication from delivery (= you), imho.
When a tunnel gets dug, you also don't always know what you're going to encounter (surprise water table? rock? skeletons?), but you make a plan to the best of your current knowledge, track your progress against it, and adjust where needed.
If you cannot do that, it looks like you're just trying to power through the project blind based on gut feeling alone.
Same as if you're a contractor. You propose a plan so they can track progress, estimate it so they plan for dependent stuff, and adjust the plan/timetable when issues arise (and communicate plenty and plainly). While I don't know GP's project context, I'd go with a test checklist and measure against that.
That's insufficient communication from delivery (= you), imho.
When a tunnel gets dug, you also don't always know what you're going to encounter (surprise water table? rock? skeletons?), but you make a plan to the best of your current knowledge, track your progress against it, and adjust where needed.
If you cannot do that, it looks like you're just trying to power through the project blind based on gut feeling alone.