Yes, we say the Leonine prayers after our Low Masses, and no, I'm never fearful of spitting out particles, because the few minutes left between HC and the end of Mass -- after Last Gospel and all -- is sufficient time for the host to have dissolved. Whatever remaining particles would be left, if any, would be very tiny and actually difficult to spit out. It would take significant effort to do so.
All of which tells me that you should bring your scrupulosity to the Confessional or to Spiritual Direction.