A cervical cone biopsy suture that measures 1.1x1x0.6cm is almost equivalent to what exactly? how much has to be taken away to have incompetent cervix

That depends!: Having a cervical cone biopsy is done to treat precancerous cells on the cervix. Most likely there was an important reason to do so. This can cause an incompetent cervix depending on the cervical length that is left. The average cervix is 4 cm. It matters the most how much the inner layer of the cervix measures and that it is closed. If it is less then 2.5 cm you may need a cerclage when pregnant.

Unlikely : Cone biopsy usually will not result in incompetent cervix , when untreated results in miscarriage. , most of the cervix has to be taken away to cause incompetent cervix , some times in order to preserve reproductive function in young the entire cervix , upper vagina will be removed as in (radical trachelectomy ) that will result incompetence of cx.