Does the rule of thumb still apply that you don't order a wedding cake to serve as many invitations you send out? If so, what is the ratio - half, two-thirds??

This may help you.

http://cateritsimple.blogspot.com/2009/07/debis-60-rule-or-why-rsvps-dont-work.html

Thanks kelleym, that helps me tremendously!!

And the best part is that all of IndyDebi's blog posts are helpful!