which exposure time for 60p and 30fps export

Hello,

I'm new in filming and editing movies. I have a Sony A7 now and whould like to do some short sport action movies.

How does I have to set the exposure time on the camera?
I figured out to set the double of the fps. If I shoot at 24p I shoud set it so 1/48. If I set it slower, than the movie and transition will be smoother and more blurry. If I set it faster, the movie will be sharper, but some unsmooth movements can accour.

My question is now, is it also important for 60p or only for 24p and 30p?
If I record with 60p and export it later in final cut to a 30p movie with some slow motions, shoud I set the exposure time near to 1/60 (because it will be 30fps export) or to 1/120 (because it is 60p record) or even higher?

How is the movie, if I set it very high like 1/1000 or even higher (because of the non-existing ND filter and filming on the beach with bright sun)?

Thank you very much in advance. And sorry, my english is not perfect.
Best regards from Germany