My suggestion would be to try the following:
Set Case 1, 61-point automatic selection AF, and set the initial AF point to where the model's face will appear when she walks out on stage. Pre-focus in that area (you can pre-set it on the lens), wait for the model, with your finger on the shutter and thumb on the (back button) AF button. When the model enters the frame, lock focus on her face, WAIT FOR THE RED LIGHT CONFIRMATION, and the fire away in high (or maybe better, low) speed drive mode.
I haven't shot runway in many years, but your other option (the only option I had back in the day) is to use one-shot AF and hit the key moments of the model's walk, stop, turn, and any other special moments (like a look back or jacket over the shoulder).