[Stiglr]

That's a decent plan for a simple (low-poly) seat. A lot depends on how much fine detail you need. It might be a bit more complex if you actually need to have the seat articulate, or if it needs to be viewed from close up. Or, if you need to create separate objects for the seat, the back, the headrest, the armrests, the armrest controls, the mounting hardware, etc.

I wonder why you would need any kind of cut-away, though. If you create a simple side profile and extrude it, you would only need to extrude it to the proper width. No need to cut anything away, just vary the width.

There's another thread on here recently about the wisdom (or lack of same) of using booleans. I think our consensus is that booleans are more trouble than they're worth. They create a LOT of mess for anything but the simplest of operations.