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

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.