@Brett Morin Thank you for your question and your patience on this matter. This was a difficult question to get an answer for as we did our own testing and ended up reaching out to the product group for verification of our experience.
The answer to your question is that there is only a inbound message per second limit for broadcast cases. So please ensure this is truly your use case.
If so, then more messages can be received per second but there might be a bit of a delay in processing the messages. The product group did stress though that anything over 2 messages per second could lead to instability, so we urge caution if you expect this to be a normal scenario to go above 2 per second.
We hope this provides you the clarity you were looking for. If you have any further questions or concerns on this matter, please let us know.