Actually, I apologize for not updating this thread. Talked to Ray today, and he said to use an adjustable wrench because the size is not standard. I went to HD and got a small Husky adjustable wrench and it worked.
Hey, been there, done that, and if you use a bit of tape on there to prevent marring, the wrench size that "almost fits" will fit well, and work like a charm while not marking up the brake in the process.
The closest would be a 20mm. The adjustable worked well for me so I have no need to try anything else. My first choice would definitely have been a proper size open end for sure if there was one