Thanks for your very interesting response.
BTW, Zenni no doubt ships to Canada.
You've reminded me that there is more "grist for my mill" as well. There is a definite conspiracy (economic) in the fact that anyone can walk into a dollar store and by POSITIVE diopter lenses, but you can't do that for NEGATIVE lenses... in other words, we myopes are being strongly discriminated against.
Hmmm...