Toy Dog Harness I'm Looking For A Pattern For A Dog Harness?

I'm looking for a pattern for a dog harness? - toy dog harness

I need a harness for my Chihuahua, but when I try to find in the store to take advantage of small breed are too small and the small regular straps are too big. Does anybody know where I can be a model for a dog harness to be found, so I make my own for his convenience? THANKS