Again, temperament and personality are the keys, as is the chemistry between the two dogs. The best test is to take your dog to meet the new dog before you adopt, and let them spend some time together. Eskies overall are not considered large dogs. The absolute factor in Eskie size is height, toe to shoulders, rather than weight. The AKC and UKC have slightly different breed standards.
Weight can fluctuate based on the dog's bone structure and diet history.
Some rescue Eskies have come from neglectful environments and can be underweight or overweight.