Standard Exec Lowest offering offering on YYZ-SFO is typically Z30EX (30 day advanced purchase)

AC currently has a sale on Exec Lowest for US thanksgiving and the December/January holiday period (24-27 Nov, and 17 Dec-8 Jan), and those are 7 day advance purchase fares in Z and D class.

I used the code on a ticket on that route earlier today in Z.