No need to play the lottery if you are happy to fly with AC. Buy a Q now, 3 days out if there is upgrade space, turn your Q into a Y. No change fees or anything when going to a full Y. You still have to worry about the return, but that is a different question.

I assume they are keeping C at 0 or 1 as they expect the flight to be oversold. This is usually the case on this route I think in summer. I am flying YUL - CDG in May in J, only showing a couple of unallocated seats in the J cabin now, and Y looks full.