Dogs are highly variable in height and weight. The smallest known adult dog was a Yorkshire Terrier, that stood only 6.3 cm (2.5 in) at the shoulder, 9.5 cm (3.7 in) in length along the head-and-body, and weighed only 113 grams (4.0 oz). The largest known dog was an English Mastiff which weighed 155.6 kg (343 lb) and was 250 cm (98 in) from the snout to the tail. The tallest dog is a Great Dane that stands 106.7 cm (42.0 in) at the shoulder.
Yes, though it is usually better to use dog clippers if you can get them. Dog clippers are designed to cut dog's hair, which usually has a coarser top coat and a softer undercoat, but not every dog has this type of coat. For instance, Yorkies and similar breeds only have one type of hair, more like humans, and so it actually makes perfect sense to use human clippers on this kind of dog.
Please note that regardless of pet type, we always put safety first. Sometimes pets can stress in new situations. If we feel your pet is too stressed or showing any potential health concern, we may opt to conclude the grooming appointment in order to do what's best for them. Your stylist can help recommend a grooming service for a smooth introduction, such as a Mini Make-Rover. For any potential health concern your stylist will refer you to your veterinarian.