Our approach to achieving a real level 5 finish involves much more than spraying on a coat of self-leveling product. We start with our extensive Framing Prelim. Setting this early precedent is key to establishing a flat base.
We always recommend 5/8" GWB for level 5, as this adds minimal additional cost while providing substantially more rigidity to both ceilings and walls, boards are ordered in lengths up to 14' 8" to eliminate as many butt joints as possible. Those joints that are necessary are backed by "Butt Boards" which serve to recess the untapered ends of the sheet, and allow an actual flat finish rather than just a feathered out illusion. All of the GWB is glued allowing for minimal use of fasteners and providing the added benefit of added sound attenuation.
Our finish is accomplished by a full hand-applied putty coat over the entire surface. It's the only way to finally homogenize the subtle differences that are highlighted by critical lighting, dark colors, or any sheen to the paint.