Definitely 8AM, if one can have a vote for it. (10PM would be here in Finland something like 6AM: so if I would like to catch up with the writing of this bunch, I would have to wake up at 4AM the latest - and then stay awake the whole day.) Well. If the game is good, one might think about it...
Retractable votes have their pro's and con's. They can be misused, surely, but they also make it possible for everyone to vote with thought in the end. F.ex. in Farael's game right now, there have been occasions, where someone has had to vote early, because s/he has not been sure, whether s/he's able to come back - and not voting is bad sport anyhow. Then it's nasty to hang around the game at the last minutes (as it has turned out possible to be there) and see, how differently - with additional information - one would have voted.