You definitely don't want to open the incubator unnecessarily now that they are pipping. That risks losing humidity and drying out the membranes, and then your ducklings won't be able to hatch out. Best to leave them alone once they have started pipping (I know it's hard but it's for the best)...
How exciting!!!! Yes, this is the time when it's best to sit on your hands and just watch the magic happen. ;) Good luck with your hatch and keep us updated! Post pics when they're out. :)