Massive stars in WR+O systems are in a unique phase of their evolution; their strong and dense winds are thought to significantly affect their future evolution into GRBs, SNe, and ultimately inspiraling compact objects. Our team is carrying out an observational spectropolarimetric study of southern, WR+O star, colliding wind binaries to characterize their shock and wind structures using the RSS instrument on SALT. We present a comparative study of the WR 21 and WR 47 systems, two WN+O binaries with short orbital periods. We have good orbital coverage of both systems that shows the variations in their optical polarization are phase-locked. With these observations, we are able to fully map out their 3D wind structures. In particular, we will focus on how their polarized line profiles vary with phase and how information derived from those line profiles relates to wind signatures seen at other wavelengths.