Both will do. You need a hydrophilic polymer (not PS), such as Ultrahydrogel, or a silica-based diol packing. I think that you will have more flexibility with the pore size distributions of a polymer packing. On the other hand, it appears that you are a novice, and silica-based packings are more rugged than polymer-based packings.
MW alone is not enough information with respect to the best pore size. However, you can select an Ultrahydrogel linear, and it will cover the range that you are interested in. Alternatively, the Protein-Pak 300 SW is a rugged, silica-based packing that appears to have the right pore size for your stuff. I can be more specific, if you specify the polymer that you want to separate.
Reason: The size of a polymer is not a function of the molecular weight, but a function of the structure. Different polymers have a different size for a particular molecular weight, and SEC is size-exclusion chromatography.