Depends - I shun this like the plague because whenever I’ve tested it, I don’t really rate a xbillion compile time over a slightly better lit map.
I get the impression people use radiosity often to brighten up darker areas, but it’s simpler to just pay attention to your lighting as you create the map. That or be lazy and add an ambient light, or set the minlight value (both fudges, but fudges that can work if not overdone).
Bear in mind, nice though radiosity is, as a lighting model it tends to work best with bright surfaces, preferably saturated. ET doesn’t tend to be that bright (although more so than the monochrome world that is RTCW!). Also, the lightmap detail level is too low to really catch much of the subtlety that radiosity can bring.
So try it without first, if that’s fine, then don’t worry about bounce. Don’t expect it to make huge differences to anything other than compile time 
In radiant for a final compile then, you want to use one of the following 2 options:
- Q3MAP2 (final) BSP -meta, -vis, -light, -fast, -filter 2
- Q3MAP2 (final) BSP -meta, -vis, -light, -fast, -filter 2, -bounce 8