Either let season ticket holders enter a ballot or sell on a first come first served basis.
There will be a number of season tickets returned. I can't see a family of 3 or 4 keeping their season tickets, when they only need 1 streaming pass.
I suspect that not all season ticket holders will be comfortable returning anyway, so 2,000 ticket might be enough?
Shame for non-season ticket holders, but at the end of the day, season ticket holders are paying around £14 per game for a stream, but the Club are selling it for £7.50, so this benefit of West Ham tickets is deserved.