Free tool
Find the hour that works everywhere.
Add the cities your people are in. Every hour of the day sits side by side, working hours shaded, and the hours that suit everybody are marked. Daylight saving is handled.
Then meet without the app wrangling
Send one Meetful link. Everybody joins from their browser, wherever they are, with no account — and every word is written down under the name of whoever said it, so the people who could not make the hour can catch up.
Just two cities?
The best time to meet between any two cities — the hours both are at work, the easiest half hour, and every date in the year ahead the clocks change. For example New York and London.