Ok, so safe to say that you didn't get the targetted promotion (letter in the mail)?
First of all, I would switch your LHR-YVR-LHR flight to LHR-YYZ-YVR-YYZ-LHR (or via YUL if you prefer).
Going via YYZ or YUL will give you around 11300 Q miles versus 9450 on LHR-YVR nonstop. Combine that with the 25% miles for being in C class, you'll get 14125 Q miles for going via YYZ or YUL.
If you don't mind telling, what's your current Q miles balance? (That makes it easier to work this out)
You could consider doing things like YVR-YYZ-FRA(or CDG or MUC)-YYZ-YVR over Dec 6-8 in full Y and then upgrading. That'll only cost you $3000.
So depending what your current balance is, I don't think you need to buy full J. Full Y should be sufficient if you're looking for an upgrade.