If you mean how to seach for any of those new attributes on Google Base you are not alone. We have fixed our GBase feed and in half the searches I've done, there are no attributes to filter with. I think that the full functionality of these additional attributes are not being used yet. If GBase accepted your feed w/out errors then you should be okay. I suggest just spending some time in Google looking for your products/items and playing with the attribute filters.
I you are looking for a great tool for optimizing your gbase feed, check out www.singlefeed.com.