Command Line Narrator



I have been using the command line version of pipeline more than the GUI lately, its very handy to quickly batch multiple books and leave them overnight, however I have some questions about the parameters and functions.
Is there a way to set the mp3Output (IE --mp3Output=false) value as a parameter or do I need to edit the value on the script file every time I want to switch between mp3 and wav outputs?
Similarly, is there any parameter that can be used to switch the TTS voice selection without having to change this at the control panel? this would make a lot of sense in the context of batch files left processing overnight.
Also is there a way for TTS narrator to output a log file? it would be useful if there is an error processing one of the books.