Crowd last August in the Australia Cup R32, South Melbourne verus Phoenix was 4,196 (35% of capacity)
Admittedly that was a cold Melbourne Tuesday night. But no bigger than a standard Western United game.
https://www.austadiums.com/sport/event/30243
Re Imanix above, the new NSD is definitely an effort by Football Australia to bridge some of that disconnection between the old NPL/NSL clubs, and the A League.
Will some of those NSD clubs then later on get admitted to the ALM? Who knows.