It obviously always depends on what you’re trying to achieve but I find it easier to control playback directly from the Metasound source and instead use the BPs to send trigger msgs e.g., start/stop, bpm changes (floats/ints) ]. As I understand the Quarz system is underlying so no need to access
it outside of the Metasound graph. Here’s an example of how the Metasound can be set up.