Hi, this is more of a tiling question I think, maybe someone can advise me. I'm putting a tile backplash up the wall at the back of our counters and the wall is uneven. Because of this, I've decided to mount the tiles with blobs of mortar on the back of the tile rather than comb the mortar out on the wall. I've never really known if this is acceptable, or if there are drawbacks to this approach to mounting tile.Can anyon tell me?