Exactly when do I redeploy units via Cunning Strategist?

[Sagittarii Orientalis]

Cunning Strategist is one of the unique command traits for armies with Stormcast Eternals allegiance.

Following is the  rule for Cunning Strategist, on Stormcast Eternals Battletome Page 95.

<Once both armies are set up, but before the first battle round begins, select D3 friendly STORMCAST ETERNALS units. They can each make a move of up to 5".>

My question is, exactly when do I "redeploy" these units?

Is it before the player who finished the set-up first decides who takes the first turn? Or is it after?

[aquietfrog]

The basic 4 page rules says the battle round begins by both players rolling for initiative. For the first battle round, this is defermined by who finishes first instead of rolling dice.  I would say the redeployment is after setup but before choosing who goes first.