The Chotki is a different form of prayer entirely, it just uses beads/knots when used as a devotional. It is more or less meant to help you in developing the ability to “pray without ceasing” (i’m simplifying), and not to meditate on any one specific thing or mystery. To effectively pray the Rosary, we generally do it on it’s own time where most of our attention is focused on Rosary and the mysteries. The Chotki is meant be a prayer ongoing in the background of our daily life, reverberating in our heart, while going about our daily business, working, and focusing the rest of our attention on other tasks…again, so that we are praying “without ceasing”, as St. Paul tells us to do.