I just created the first two events, both Friday and Saturday at 9pm in my timezone (CEST).

I assume steam shows your own time zone instead of 9pm. This was just a wild guess on my part which time would be convenient for most EU + Asia players but ideally I'd want to use some scheduler voting software to reach an agreement with the "core players of this group" in order to establish a regular time that best fits our private schedules.

Suggestions on how to coordinate? I always used quick doodle polls before to accomplish this but now the program is not free anymore. Any free alternatives without a need to register to make it quick and painless?