As host for the event, I am partial to no particular date, and want only a couple weeks notice prior to the date.
I want as many to come as can, and want to put no restrictions on any date which will work for all.
That said, please, decide upon a date, and we will make it work. I do not see a need for a poll. I would ask only that we zero-in on a few dates, then pick the one that works best.
I really look forward to the event, no matter when it is!