Wait and see. I think if the statistics by then show that it is likely no one in the stadium has it, or just 1 or 2 people, any restrictive measures would be unnecessary. Reduced capacity pretty pointless in that scenario and would have real financial implications for all the clubs.
Dare I say...
I think 100% capacity much more likely.
Infection rate at 1 in 4000 and dropping means 40% capacity or 100% makes little difference in reality.
If there is reduced capacity this will be a tokenistic measure designed to engender confidence.
Unless rates increase between now and then.