I've only flown J in North America from YYZ on AC or in SE Asia between different countries/cities but never internationally from YYZ.
I've used the business class check-in counters at YYZ TB area (aisle 7/8 I think), but I highly doubt that its the same one for Intl flights (maybe?).
Is the Intl business check in by Aisle 1, or the one by aisle 7/8? or another secret location?
I found a press release from January where AC stated its by former Aisle 1, but then also read some people complaining they couldn't find it and walked by it
On a side note, I got seat 1A on 789 +1 to ExpertFlyer for the seat alert.