Patterns are not designed for superdogs

I have a very simple pattern for 4 styles of dog coats which I wanted to master before attempting the costumes. I must say, that after making 2 of the easiest coats, some dogs must really be damn tiny. The coat length part seems totally normal but the necks are very tiny. The first one is too small to fit around Princess Caicó who is not at all interested in being a fashion model, especially of canine fashions when she is far superior to them. The second attempt is better but still not quite there; the neck/collar only comes to around 11". My third attempt with different fabric (fleece instead of flannel, what a bitc*!!) has been more awkward and I've had to wing it as far making the neck bigger but not the length of the coat. And I detest the way the instructions say to attach the collar so I spent an hour ripping it off on New Year's Day (good thing there was a Monk marathon on to keep me sane.) I need to get back to it today because I might go see Trixie & Daisy on Saturday.