Profile size selection is based on the thickness of the tile and amount of setting material used to set the tile. With smaller format tiles, take the tile thickness and select the corresponding size profile. Due to more warpage with larger format tiles, additional thin-set mortar may need to be applied underneath the tile to achieve full coverage. This will raise the tile and may require the use of a larger profile. Once installed, the profile and tile should be flush with each other.
Please see the Tips, Tricks, FAQ video, "How to Choose the Appropriate Profile Size in Relation to Your Tile" for information.