I've thought about this a lot. I finally came to the conclusions that you should do what you think is best for your business. You can simply think of a self vote like marketing. On the other hand, some curators shy away from posts that have been self-voted. A compromise could be to wait 30 minutes before you give yourself an upvote. Personally, I think as long as you are also spreading votes around and helping some other good authors get visible, you should not lose sleep over your choice.