Another case where my favorite flight (BOS - YYZ - YVR with an overnight layover in YYZ) has no Y, but quite some J.

Not wanting to wait the Y to be available at the last minute (which it may not), I plan to book my second best option (BOS - YUL - YVR with an overnight layover in YUL) and comp upgrade it to J. I suppose I can then SDC it to my first choice when the checkin is open (if the J cabin is still available).

I do not see any hole in my plan, but would like to hear critics from more experienced flyers here! Thanks a lot!