In reply to Jaymac23:
I did the Gouter route some years back, when it’s permissible to bivvy around the Tete Rousse, however now strictly monitored and impossible to do. There were hundreds of us bivvying and everyone got up around 00:00 and got going by 00:30 to ensure you’re on the summit by 07:00 (if you’re fast) and back down past the Grand Couloir before 10:00. Even then, that’s arguably too late.
A friend and I foolishly crossed the Grand Couloir late afternoon last summer after doing the lengthy Innominata. Just 30 seconds after crossing it, thousands of rocks came firing down, many the size of microwaves! Yet behind us, there were still numerous parties similarly descending. Lucky none happened to be in the firing line. It’s certainly much much safer at night, but given the lack of a refreeze many nights in the Alps with warming temperatures, it’s a death trap that is normalised, simply as it’s the Voie Normale up Mt Blanc.