I go for size too........and also consider medium a cocker, a pit, a bull terrier, a bulldog, a dalmatian, a schnauzer..........

husky, lab, rottie, dobie are big...........on the bigger big, akita, shep, malamute

and huge come the saint, dane, mastiff, etc........

as for small I go with pug, westie, poodle, pom, maltese

and for tiny a chihuahua, yorkie