I used to use rags sheets but in light of what i'm reading here I won't touch them again.Iwas at Aqueduct when FuPeg won the Wood ,Iseen the track super change the track a few times that day ,first they had it sealed then they harrowed it again ,then resealed it .In a span of 3 races the track played significantly different .I don't know a whole lot about variances but if this is not reflected in a product I would have alot of trouble risking my hard earned money on it.