oh - as far as my knowledge goes, the first 30 minutes after you post something, curators who upvote you will not see a return on their upvote. the golden point is after 30 minutes. So you should wait until a post is 30 minutes old, then upvote. Of course, if you are self-voting, then upvoting immediately is best.

also, the sooner you vote, the more you take the curation reward. so the idea is to discover good content early, but read it for 30 minutes then upvote ;-)

Let me know if your rearch reveals a nuance that I am missing. I have heard that this will change or may change some time in the future. Perhaps with a 'hardfork'.