Normally you would not have the spout itself in place. You would have a blank copper stub, or a capped threaded nipple, to stop any drips and provice something to fit the tile around. Don't try to be too cute with the fit...leave reasonable clearance around the tub nipple and the shower nipple. Spouts and escutcheons are designed to cover clearance holes.
This three handle valve....is it new? Is is pressure balanced type??