Yeah, I find the optimal balance between simple numbers that find traction politically, and the realistic but unpopular acceptance that things are uncertain is

Yeah, I find the optimal balance between simple numbers that find traction politically, and the realistic but unpopular acceptance that things are uncertain is a triangular distribution "least possible, greatest possible, most likely". You can plug these into monte carlo simulations with any kind of math happening between your uncertain terms, get output distributions, pick bounds to minimise risk (95% chance the release is completed on or before <DATE>).