I'm an E and waitlisted for AC15 (YYZ-HKG), Feb/13. The agent told me if it's not cleared before check-in opens, I have to re-request. To my surprise, I was advised not do OLCI. Instead, I should check-in at the airport as early as possible and request upgrade then.

Because I have a connecting flight to SIN on AC6301. SQ agent told me that I won't be able to select my seat until check-in. Therefore, considering HKG time is 13 hrs ahead of YYZ, I'd like to do OLCI with AC and select my seat on the SQ operated AC6301. Now I'm a bit confused whether to do OLCI or not. My first goal is to get upgraded on AC15. Any advice? Thanks.