Can't apply theme customizations across Multi-site

This is my first multi-site networking extravaganza.

The idea behind doing this is that the client wants the main domain and sub-domains to have the same theme and have them all customized the same way.

So, I went in and customized Blogs MU for the main domain, but now I don't know how to apply the customized look of the theme to the sub-domains.

I can apply Blogs MU to each sub-domain, but it just shows with the default settings. Is there any easy way to remedy this since I've got dozens of sub-domains?

Thanks,
Mieren