Great question - we will likely be looking at G Fonts alternatives as we are planning to revamp the entire website over the coming weeks/months.
As for "grace period", are you asking about URL/link previews and whether those have any effect on reading the secret? If so, the answer is no - the secret will only be read once the client-side JavaScript code is loaded and executed, only certain layout components are rendered server-side.
But I may have misunderstood your question, in which case please do not hesitate to ask again :)
