Reverb is usually added after the fact - the recording goes to tape dry - in the case of film scores, the mixers on the film itself want it dry so they can add what they need when they're mixing all the film tracks. If the room has a natural and beautiful ambience, like Fox, there's really no need to add anything. Other rooms are dead sounding. The Donaggio reverb is all added to the two-track mixes. In the documentary you reference, if Goldsmith is wanting wetter he's talking about the playback in the studio, most likely - one always adds the reverb when the session is going on, just so it's a nice listening experience - but that isn't going to the multitrack tapes.
Thank you. For me this is valuable information. Now I can go 'reverb-hunting'
But what venues would you describe as 'dry' sounding?