Hi!
I can't really help you with a MG specialist in Toronto but, if you don't mind heading a little further to the southwest ... At the Neuromuscular Clinic associated with the Univ. of Western Ontario Hospital in London, Ont. ... there is a Dr. Niccole (neurologist)... initially when I was first seeking my diagnosis I was sent to him as the doctors in my area suspected that I had MG. As it turned out my diagnosis is Myatonic Dystrophy Type I/Adult Onset. Dr. Niccole is apparently one of (or "the absolutle") the authorities on MG in North America ( they told me that people from all over the world come in to see him ). So, if you can't locate someone in Toronto ... try him, sounds as though he'd be worth the 90 min drive between Toronto and London, he was for me anyway ... although I'm further SW than London about 90 min further on the 401.
Hope that helps you out some, take care: Kefrin