Respected Mufti Saheb
You have mentioned that loud zikr in unison in musjids is somethimg that is not advisable or you have not come across. Does this include the loud zikr of the late Hazrat Moulana Yunus Patel (rahmatullah alaih)? For he used to in his majlis`s have zikr. His khulafa as well as many sheikhs have such zik.