Pick a time and share the link. Everyone who opens it sees it in their own timezone — theirs is detected and highlighted automatically.

Nothing to save — everything lives in the URL:
?t=9:00am&from=BST&to=EST,PST,CET,IST&label=Weekly+sync
The "in 3 hours" hint under the time keeps itself current, and daylight-saving shifts stay correct (a zone entered as EST shows as EDT in summer).