I shoot the room with a 3 way laser level and mark my bottom edge line on the wall then I use a couple of surveyor's tripods with a 2x12 on top secured to the screwdowns of the tripods to carry the system and keep everything plumb/level.

If you screw the fronts together with no gap, you can then shim the rear from top/bottom and then slide it back against the wall and shim for the gaps between the wall and boxes.

For brick I use either a Hilti epoxy system with a J channel that grabs the 1"x3" I install across the back with a Hilti threaded sleeve anchor epoxied in for the bottom (then you can just shim out and screw it down thru the back of the box)..

The Hilti HY-70 system with a screen tube is the only thing you can use with Terra Cotta Book Tile walls (very common in NYC apartment buildings built before 1940) as the screen allows the epoxy to mushroom out inside and in back of the Terra Cotta tile and the final diameter of the mushroom plug is close to 2".

Simpson Strong Tie also makes some nifty anchor systems for wall panels that can be adapted to carry cabinetry. Nice thing is they also include all the required fasteners and screw gun bits.