Worked great thanks, just had mix-matched certs.
For the future if anyone reads this thread, you don't need WPP on the offline environment, but just the environment you create the packages on, but both need to have the same cert that was generated on the WPP server.
For the future if anyone reads this thread, you don't need WPP on the offline environment, but just the environment you create the packages on, but both need to have the same cert that was generated on the WPP server.