The emulsion is what holds the detail to a large degree, or I should say the edge of the emulsion. You want a decent amount of emulsion on the shirt side of the screen to help avoid the jagged edge you get with lower mesh counts. That's why capillary film makes such a good print, because almost all of the emulsion is on the bottom, with a smooth face that aids in forming a tight gasket against the shirt. The coat on the ink side encapsulates the mesh, plus pushes the bulk of the emulsion to the shirt side where it's needed. I always coat my screens 2 wet coats over 2 wet coats, finishing on the ink side. Also dry your screens shirt-side down, again to bring the bulk of the emulsion to the shirt side.