Self level tips - Tile Advice

[Gdou9518]

I’m going to be self leveling my concrete floor I’ve removed tiles today but cannot get the adhesive off it’s solid even with a sds chisel so I’m going to self leveling it I’ve noticed with a laser the floor is 15mm out from one side of the room to the other has anyone got any tips for when laying self level compound to sort this i originally bought 4 bags I’m thing around 12 now