Mary, Kristin, Alana–thanks for all your feedback on sizing the harnesses. I’m sure a size 0 would fit for a long time to come, but the breeder told me that Mo’s mom is 55 pounds, his dad 60 pounds. He said that wirehairs from his stock almost never fall outside the typical weight range for the breed, 55-70 pounds. He told me that he’s 100% confident Mo will be over 50 pounds, and he’s pretty sure Mo will grow to between 55 and 60 pounds. Thus, I did decide to get another cheap harness and then order a size 1 Julius.
Mo’s current girth is 24 inches at the chest and he’s 35 pounds–perfect for a size 0, but also just an inch shy of the low end of the girth range for a size 1.
Thanks again for your help!