Thanks for this post. I’ve thought about this a lot myself. I’ve discussed it with a few people and the general consensus seems to be consistent with your article - it’s ok to upvote your own post, but it’s bad etiquette to upvote your own comments. I apply this thinking with my account.
One thing I’m interested in is your opinion on upvoting other people’s comments. You mention this briefly in your post. As a rule I upvote everyone who comments on my posts (assuming they are relevant comments). I feel that if someone has taken the time to make a relevant comment on my work then they should get rewarded for this. You seem to be more selective in who you upvote?
I tend to only upvote comments that really add to the discussion, I also tend to be very low on VP a lot of times due to flagging spam so I don't always have VP to upvote as much as I would like.