If she has never travelled since getting PR, then a 3-4 days buffer is fine. Otherwise, good to have at least a month or so of buffer. I applied for my wife at 1100 days and it all went pretty smooth for her.My wife has never travelled since getting PR and is now at pysical presence 1099 days , should she apply now or wait couple of weeks, also is it better to get e-certifcate or paper copy of citizenship certificate