Yep much appreciated.
I have never shot it before. Will be shooting upwards. Nothing will come between the jumper and the camera.
I will try it on 4 and see how it goes & adjust if necessary.
Just guessing here... probably all the interesting shots will happen at the apex of the gymnast's jump, which will be roughly at the same height jump after jump. Probably doesn't make sense to follow them up and down with the camera. Maybe allowing them to pop in and out of the frame makes most sense.
You may want tracking sensitivity to be low so that the camera doesn't focus on the background when they pop in and out of the frame. It may even be better to manually focus depending on how consistent they are with their jumps.
I'd probably use Back button AF and just tap it here and there between bursts with settings closer to case #3.