I just want to confirm that this error means I'm just trying to send too much at once over the link cable?

"Link message size out of bounds: 833"

Thanks for the help!

Correct. You can see where that prints here: https://github.com/TinyCircuits/TinyCircuits-Thumby-Code-Editor/blob/master/ThumbyGames/lib/thumby.py#L585

The max packet size can only be 512 bytes when using the built in link API