The WIYN Mini-Mosaic WCS was incorrectly recorded with a 180 degree rotation for a couple of years. It has been fixed recently but for older data this can be easily fixed using MSCWCS in the MSCRED package. To correct the 180 degree rotation error found in WIYN Mini-Mosaic data use the following command from the MSCRED package.
ms> mscwcs [file] ra_rot=180 dec_rot=180
To complete the WCS calibration you would still need to correct for offsets, refraction, etc. Typically this is done with MSCCMATCH.