I had considered trying out the new Comfort Class on this segment in combination from Vancouver (YVR-YYZ on AC and YYZ-IST ok TK) but it appeared that I could not get this booked on one ITIN. Seems as though I would have had to do it on two ITIN;s making it very expensive. So I ended up going through Chicago instead.
Hopefully they will add codeshares across major centers in Canada shortly.