In addition to shooting the "dress rehearsal" I do somewhat informal head shots just prior to the rehearsal. From start of the shoot to the end of processing and uploading took about eleven hours this year. I had almost 600 images from the rehearsal and almost 80 head shots to process from RAW files.
I feel that shooting in RAW is necessary to be able to adjust highlights and shadows or white balance as needed. I've learned over the years not to worry so much about white balance as the varied color lighting they use makes certain scenes look strange and that's not my issue.
I used a 7D and 24-70mm f.2.8 lens for the head shots so that I could wirelessly control an off camera flash and fill with the built in flash. For the rehearsal I used my 5D Mark III and 70-200mm f/2.8 lens. The 5D Mark III has better high ISO performance than bodies I've used in the past so I used ISO 3200 with no trouble. I'd even go higher if necessary to get needed shutter speeds.
Here are a few samples followed by an embedded slide show: