[Aussie Mike]

Sorry for the confusion. I thought you were talking about the front discs.

Yes I did drill the cross drilling on the rear rotors as well. The standard rotors are just solid with no holes. The pattern is based on something I saw on a motorcycle disc. The layout of the holes is such that the whole are of the pad gets swept by the holes at some point. I believe it ensures the pads don't develop grooves.

Cheers