Kyle my 1st natural stone job, at the ripe old age of 17. The tiler insisted I didn't "grade out" the slate??? in some slate there was anywhere between 5-10mm thickness difference. When he laid the floor, it was without a doubt one of the worst attempts at a floor I had even seen!
"steven, I will show you how real tilers lay natural stone tomorrow"
Proper old school! hammer and chisel the following day and it instantly became one of the neatest, tidiest floors I had ever seen. Long story short, you can get away with murder with natural stone. Nearly as forgiving as mosaics.
Natural stone has the same finish right through, the only thing that concerns me is "uncalibrated" mad wild for sizes and even being remotely square! a 3mm joint can easily become a 10mm joint at the end of a tile!"