"I sometimes change my vote afterwards to give them a much bigger vote if they come up with something particularly good."

This will reset/kill any curation for the old and new vote - just making sure :)

I know. When I change my vote, I do it for the user I'm voting, not for myself.

"I do self-up-vote at about 14-15 minutes but I don't think that's particularly dirty a thing to do."

In the grand scheme of things it isn't, carry on :)

I agree that this sort of daily income is years down the line, but not impossible though. One Clash of clans would be a good start, and I don't think we'd need many of these to send STEEM flying.

Clash of Clans had been downloaded 500 million times by October 2018 according to Wikipedia. A Clash of Clans on the Steem blockchain would send STEEM flying but only if onboarding were made super easy.