I wont matter if the vest is a little big in some areas. Just don't buy it to small. Most of the time I have to cut the leg openings, so they don't rub under the front legs. I put the vest on the dog, and mark the cuts. After cutting put it back on and see if I need to fine tune it. You can even cut the seams,shorten areas, and sew back together to get a better fit on your dog. I just make sure the new seams face out, so it doesn't rub the dog.
Shopping with your husband is like hunting with the game warden.
Experience is what you get, when you didn't get what you wanted.