Even if YYZ-MAD won't be serviced by the Three Amigoes this summer, you won't be able to get any historical load stats since the route has historically been served by all-economy planes.

Uneducated guess is that, if J is actually possible, an E or SE flying YYZ-MAD in June has about as good a chance at an upgrade as you're going to get on a TATL trip (other than certain YYZ-LHR flights).