I went to CM immigration today to extend my visa based on marriage (60 days). Was on a Non-b, then 2 covid visas which runs out early March. They said if I change the visa to a 60 family extension early I would lose my time beforehand. So for CM, go close to your visa expiration date otherwise you'll lose time. They also did not provide a list of what is needed for the family 60 day extension.