I don't think there would be any specific ratios for the placement of the logo. It will be left up to the designer of the ad, brochure, banner, etc. Advertisements for an institution of this nature would be at the mercy of whatever subject material is brought their way. Take this ad for instance, it was a standard ad that was given to all locations by the Moscow Ballet. Then the host venue would put their logo at the bottom.

Interestingly enough, the Moscow Ballet performed this here on Dec 2nd.