Alright, I have my SLK900U and its good, but not performing as i thought it would with the 92mm Tornado, so i think Im gunna lap the base. I dont have any glass, but i do have a marble tile thats approximately 12x12'' and i would assume is quite flat due to the fact that its a tile.. Would this be a good surface to lap on? I suppose so as long as its flat...? Thanks