Itzl's new pesticide and rain booties are in and I finally have the right size - XXS.
The XS does fit him, but the sometimes slid off. The XXS looks like they'll stay on.
I like these booties for him because they are lightweight - his acclimatization time is nil compared to half an hour with his heavy duty leather and rubber zip up quads, they are extremely easy to get on - no zippers, ties, or buttons, and they offer extreme protection from lawn chemicals, hot pavement, ice and snow melt chemicals, ice and snow, sandy beaches, and they increase his traction.
They do look a lot like balloons on his paws. In fact, they look like balloons off his paws, too - thick-walled, wide-mouthed, short-necked balloons.
Sadly, the only color in his size is yellow. I would have liked orange booties in his size since orange is the recognized color for hearing dogs and orange booties would have coordinated with his work vests, harnesses, collars, and leash.
Ah well, they do the job and yellow isn't so bad.