The size of the PDF file has little impact on the size of the eMag. Most eMags will end up at more or less the same size, depending on the number of pages in them and the resolution they are generated at. As a general rule, eMags are quite bandwidth intensive due to their rich-media nature, and should be hosted on a high performance hosting service. eMags can benefit greatly from being hosted on a Content Distribution Network, such as Amazon CloudFront, CacheFly or similar.