You can flush every two weeks and a lot of people start out that way because we are desperate from relief. It takes from 2 to 4 weeks for the older more buried stones to move forward and the newly relieve liver to heal up.
I plan to do this till I'm healed up and am passing no more stones. It will take me probably less than 6 months to get to that point then I'll be doing the twice a year upkeep.
Good luck you two on your first liver cleanses. It's a liberating experience to get free of pain that has plagued you for years.