The silence indicated in Dakshinamurthy stotram is to remind the Taittiriya Upanishad mantra - yato vāco nivartante | aprāpya manasā saha. Brahman being the subject of the enquirer cannot be known thru any pramana. It will be taught through implications. And thus it can be claimed as - AHAM BRAHMASMI - once the Dakshinamurthy stotram is taught by the Guru . No knowledge happens in silence. It has to be taught by a Guru who is a shrotriyam and a brahanishta. In Advaita vedanta there's no mysticism. It's the knowledge of the SELF that has to be gained in full wakefulness state. Jagrat avastha. With a very sharp intellect as the topic is arma, the subtlest of the subtlest. Remember, if any such mystic ways were accepted by the Vedas, then Bhagavan Krishna would not have spent chanting more than 700 verses in a dialogue with Arjuna. This doesn't rule out the personal experiences, prathyaksha anubhavam those devotees of Bhagavan Shree Ramana Maharshi had in his presence wrt Dakshinamurthy stotram teaching.