On days such as maasikam, sraddha, amavasyai, etc., must the sumangali ladies wear only a simple 9 yards cotton saree? Or are they allowed to wear sarees with silk zari border or Kalyani cotton sarees? Can 6 yards saree be worn like traditional 9 yards sari?

On maasikam, sraddha, and amavasyai days, the wife of kartA must wear only the pure clothes that were hung out to dry after sunset the previous day. It is not a practice to wear a 6 yards saree in a 9 yards saree fashion. Only 9 yards sarees must be worn.
Notes:
Usually, it is not a practice to wear silk sarees on days such as maasikam, sraddha, and amavasyai. Since the silk sarees contain zari and some are not appropriate variety. Some types of ordinary zari must not come into contact with vessels at home. Cotton saree does not impact such deficiencies and it is better to wear only cotton sarees.
In some households, it is a practice to wear silk sarees on maasikam, sraddha, and amavasyai. Even those silk sarees must be washed and dried after sunset on the previous day. Follow the practice of the respective households.