Good thinking Mr GTX and it aligns with how a blitz GB usually goes.
The idea is post a start pic with a clock and then a few updates and final pics with the clock.
The posts themselves can serve as a time-stamp as well. Usually things are pretty loose because no "winners" are chosen. One wins by completing their model within the blitz.
Extra points for posting your snacks, beverages and/or lunch.
I once blitzed a kit that was so horrid I was tempted to post pics of the pharmaceuticals I'd need to finish it.
Brian da Basher