How many units should an opponent have to confidently run Coterie of the Conceited?

Basically title, I’m new to this army and want to play this detachment but I only have 1500 points worth and that’s the biggest game I can play.

The stuff I typically play against is Adeptus Sororitas, Custodes, and Orks, leaning a lot more on the Custodes side, having 3 different people I play against that play them.