First and foremost, see if you can get fuznuts, or whoever has the access rights to it, to post these kinds of announcements or planned events in the welcome message of the mumble server, that is the first place if should be posted imo.
I can only vote for a single day in the poll, for me as long as it is one evening in the week it doesn't really matter which evening that is, because I can try to reschedule around it.
Another point is, is this meetup focused on bitshares or is it more beyondbitcoin? If it's the latter then this poll probably should be crossposted on a number of the other forums, where people are trying to wrap their heads around other applications of decentralized technologies.
My last suggestion for the moment, for the time this poll is still running, would it be possible to just set a time that would fit your schedule Delulo and see how many people show up? Possibly try and anounce a couple of different days and see when most people show up, or during the meetup discuss what time would be most convenient.
Oh, just thought of another one while writing the last paragraph, so this will really be my last suggestion in this post. Maybe posting a central topic (or a number of them) for discussion or some questions (might also be an offer to explain what bitshares is all about, because I could conceive of people being confused and looking for some help) might make more people interested in participating no matter the date and time.