Interested in a new Mac to run both OS X and Windows. Currently, planning storage and backup. Having read that, "Time Machine needs 2 to 4 times as much space." So, would like to use two external HDDs each with Mac and Windows partitions. One would have a OS X data partition and a Windows backup partition. The other would have a Windows data partition and an OS X backup partition. This is diagrammed below. This should work okay, right ? Thanks for any feedback.