Interestingly enough I came here searching the same issue. 
 
	12 x 24 tiles do not represent well. I have tried so many ways. 
 
	Today I downloaded Substance Player and made my own however you are not really choosing the size of the tile, just the ratio. 
 
	So when I applied the Maps the size are smaller than the tiles on the floor. 
 
	The grout is a light gray so its tough to see.