Thanks man.
Yes I went with 6 days on the comments because of that cutoff time. Like @sparkesy43 confirmed, they give you an error for comments that are on the time limit.

Oh yes, some people don't like last minute upvotes on their normal posts because it would have had a bigger reach had they been upvoted sooner, but I think when someone is in the position of asking for help they really don't mind you going through their older posts. You can only upvote someone once after all :)
Also, after the first 30 minutes it makes no difference to the original poster in terms of payout vs. curation %. Only visibility is affected.

In the same way I know people who freak out if you dare upvote your own post, but as I see it, upvoting my own post means my followers get a bigger payout on their curation rewards and besides, my upvote is worth all of 6 cents at full strength. I try to upvote every good comment on my posts, so that way people are being rewarded for interacting anyway.
Currently my voting power is going to take 64 hours to recover from my voting spree yesterday :)