That's impossible to answer given that this depends.... It's a GIC prerogative to do that and normally it would take more than 30 days. Especially on national security, we may need to vet the person and so on.
Just to be clear, proposed subsection 5(1) is the process for the acting chair. If there is no chair and no vice-chair, the process is there to appoint an acting chair, and then there's 90 days for the Governor in Council to appoint a chair. So you have three months to find a chair if, for whatever reason, the chair or vice-chair is not there.