Good post about the upvoting-topic. I did not have a guideline on this, so i made a blogpost about it as well, since i wasn't quite sure whats the best line to take. Would be great if you could respond to it. One thing you did not mention is, that besides the financial aspect, upvoting has a ranking aspect. An upvoted post, wether its a self-upvote or a randowhale upvote, does increase the time a post is highlighted in the relevant tabs(new, hot,trending). Same goes with comments , they would rank higher.
https://steemit.com/steem/@steemboys/upvotes-what-s-the-best-way )