My understanding of Polyclar is that it clarifies, and has some antioxidant properties that help to ameliorate browning and oxidation that might have already happened to your wine. In winemaking it seems to be used after fermentation has ceased to stabilize the wine via antioxidants, rather than stabilizing the wine by stopping future fermentation. It can be used in a preventetive or remedial fashion, so either because you are worried about oxidation, or because you are pretty sure you did oxidize your wine. It seems to me that these two have somewhat different properties, so it would seem like the best bet would be to go with whichever one better suits your need (so k-sorb for stopping light present or future fermentations, or polyclar for preventing oxidation.) Apparently Polyclar is polyvinylpyrollidone which binds oxidized phenols.
Give a man a beer, and he wastes an hour;
Teach a man to brew, and he wastes a lifetime.
-St. Louis Brews