What is the minimum distance fans can be from the pitch in a new stadium???

[JudoRanger]

Distance also depends on whether or not we want to be able to host European matches - e.g. Cham League, Europa League etc.. as they have minimum distances.

I went to a few stadia for a uni dissertation for my architecture degree and one was Southampton - they have massive distances to allow them to play european matches if they ever qualified/wanted to host interrnational games etc...