From about 1 November, there have not been more than 500 pilgrims on any day. I have been watching the daily numbers each day.
This means that the 2019 Camino season is OVER. The number of pilgrims is falling to a typical daily number of from 200 - 400 pilgrims.
You should have no problem getting a Compostela, regardless of what time you show up. Check the office hours. I think they open at 0900 from here on out. They MAY have discontinued using the QR ticket system as the daily volumes are so low. But, I do not have good knowledge of this.
Excepting long holiday periods, it will remain this way until next Semana Santa / Holy Week - the week immediately leading to Easter. In 2020, Easter is on 12 April. So, Semana Santa starts with Palm Sunday, the previous Sunday, 5 April 2020.
Second, I think there is a night train from Madrid that puts you into Santiago early in the morning. Itis one way to spend 11 hours on a train... just sayin...
Hope this helps.