The lab calculators: what a strip draw means in hours, what point LEDs cost your battery — free, in the browser, with the printed sheet for the bench.
Paint reads from the back row when the contrast is high — go darker than feels right. The saved PNG is yours: print it as a paint guide for the real dome, with the weathering sheet beside it.
hours = Ah ÷ A — draw per meter from the cheat sheet. White-full is the ceiling, never the plan; dimmer presets are the plan.
mA = LEDs × 20; hours = mAh ÷ mA. The watch itself budgets ≈40.5 mAh for the app — power saver kicks in at 8% and clears at 15%.