With render engines like Cycles and iRay, you tend to have to let the render engine do several passes before you get a quality image if you're rendering passes with Superfly you can render passes or have it do a full render right away, which was something else I didn't know about until recently.

Your description bears no resemblace with the Cycles I have used in the last 4 years. Render passes are e.g. diffuse, specular, z-depth etc. which have nothing to do with the number of samples and the integrator one can choose for Cycles which have again no connection with the tile size used by the render engine. I am mistified to the max about this "thing" and its relation, if it has one, with Cycles.