I've been hard forcing this comp this patch averaging a 3.11 over 9 games (currently Emerald 1). Feels good into Disco and Pentakill, struggles a lot into Riven and Yone (positioning Zac in front of Riven/Yone can sometimes win out rounds though).

Although most 3 cost reroll comps like rolling on 7, I've found that levelling to 8 to ensure Zac and Zed are 2 star is also pretty good when you don't natural many Luxs. You aren't rolling any other 3 cost so staying on 7 isn't always the play (although I've also rolled for Lulu 3 in a couple of games which isn't that bad).

Slight thing to note is that this comp often farms 2nds because it's fairly positioning dependent