Systems Deployment

Im deploying Windows 7 to XP tools boxes I have in production.  My target systems have 2 physical drives.  Most have the following configuration:

OS- C: 200GB

DATA- D: 750GB

Im noticing that on a 2 drive UEFI system when I boot into Windows PE for OSD drive 0 is not alyways my OS drive.  From what I read Drive numbers are dynamic in UEFI.  The SCCM OSD task sequence targets a drive # so I would think this a common problem.  

My solution was to provide a variable on my Partition drive 0 to check on the following WMI query:

SELECT * FROM Win32_DiskDrive WHERE Index = "0" AND Size < 250000000000

or Partition Drive 1 for

SELECT * FROM Win32_DiskDrive WHERE Index = "1" AND Size < 250000000000

the problem is, we have machines that are showing up in reports with 2 small drives or 2 large drives.

Does anybody have a more elegant solution for partitioning that drive # that contains c:?  I cant loose the data on my d:.

Thanks!