Maybe get better pepper spray, also make sure it's the stream spray type not mist and make sure it's in their eyes/up the nose, if you dose them properly and the dog is still in exploration mode there is no way they will not stand down after you do that.
Don't wait for the situation to escalate before you use it, once certain dogs are locked into attack mode they are neigh impossible to control unless you have a baseball bat at the ready.
Granted just as with humans some individual dogs or breeds probably have a mindset thats more amenable to allowing them to block out the pain but that doesn't discount usefulness of pepper spray.
"If your dog is sprayed with pepper spray, they are likely to be experiencing a significant amount of discomfort. Pepper spray causes significant burning sensations in the eyes, nose and mucous membranes. This non-lethal weapon has the same effects on dogs as it does on people."