What will be a good time to queue for Berlin?

Hi Everyone

Travelling from the UK to Berlin to see gaga next week and wondering on a good time to join the queue?

For night one I have GC standing although it’s not early entry and for night two I have general admission standing. I know I’m not going to get the barrier or anything and that’s absolutely fine but still want to be as close as I can without standing for hours before.

Thanks