What I do now, I gather some 10-20 EPUBs purchased from different sources, then batch convert them to MOBI using Calibre. Then I add them as attachments to my

What I do now, I gather some 10-20 EPUBs purchased from different sources, then batch convert them to MOBI using Calibre. Then I add them as attachments to my mail and use Send-To-Kindle. The MOBI files are barely hundreds of kilobytes, and I can fit about 20 books in a single email.