I posted a video
of my routine, shown below for easy reference:
My pace is a little faster than yours, averaging around 90 seconds drink-to-drink. That's enough time for the group to stabilize and no flush is required. The PID setting is 254°F (~1.2 bar).
The Pro 800 is a reasonably fast steamer, but it's slower than the Speedster and La Marzocco GS/3 I've used at the same event. That's no surprise, given the latter are double boilers with steam boilers set to > 1.5 bar. You can see the impact of faster steaming time:
The Speedster's drink-to-drink time is comfortably around 60 seconds, even for a non-pro like me. One drawback of the Pro 800 under load is that you cannot raise the steam boiler pressure to reduce steaming time without impacting brew temperature. Then again, one drink every 90 seconds is no slouch pace!