My standard 14" rims take 185/70R14, and if you look on
this site, you can see (at least it looks like) 195/60R15 is the appropriate size for plus sizing; 205s would just be wider, and therefor shorter sidewall to fit properly. And yes, you always replace snow tires --> all seasons or reverse in groups of 4, or you mess up your traction. Our winters here are pretty light snow wise, although it is the cold (and therfore the ice) that might get you. Although, this big storm coming through is suppsoed to dump 6-8 inches, so it all depeneds on what happens, lol.
BTW, I am about 15 min from the Southern Ontario border, so yes, it is prolly very similar.
