I know there are a few who grumble about 'auto-votes' but this really is such a useful tool if used correctly. I'm similar to you in that my mana limit is 90%, so that I can reward interesting posts manually, but if I don't check peakd for a couple of days, then I'm still getting the autovotes to maintain my curation rewards
All of mine are set at 9 minutes, because I believe there used to be a decrease in rewards if you voted before 5 minutes, but now the rewards are linear, I think I'm going to change all mine to 0 minutes like you mention
The only caveat I would add to your post is that I only add users/authors who I think are consistently 'interesting' and deserve that consistent reward. I do check Hive.vote from time to time to review this and make sure all the people on there are still being interesting, and I update (add/remove) accordingly.
This really is a tool that everyone should be using to maximize their curation, thank you for developing/maintaining it!