Welcome to FT.

You should read the Wiki at the start of the thread which will answer most of your questions.

The biggest issue is that at 25K you are close to if not at the bottom of the priority list. The chances of upgrading from economy to business on an Air Canada route to Asia is pretty close to zero unless you can find a flight that can has upgrade space from Latitude immediately but the odds of that on short timeframes are low. If you bought a Premium Economy seat your upgrade odds would be a bit better but it is still pretty bad. Don't book an economy ticket assuming you are going to be flying in business via eUpgrades as a 25K.