When using btdownloadcursus,py you can not change those things on the fly as far as I know. You will need a restart.
You might take a look at BTQueue a console-based BT-client which actually allows you to do change a few options on the fly and the best of it all it's build on top of BitTornado.
BTQueue has real nice information features too like the normal BitTornado gui, something that the current gui-less versions are missing.
url:
http://btqueue.sourceforge.net/
Too bad it has little documentation, but if you need a hand in using it I'm willing to help.
They 've got their own forum btw.